dataframes.ipynb

{
 "cells": [
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# `DataFrames.jl`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Julia Version 1.10.1\n",
      "Commit 7790d6f0641 (2024-02-13 20:41 UTC)\n",
      "Build Info:\n",
      "  Official https://julialang.org/ release\n",
      "Platform Info:\n",
      "  OS: macOS (arm64-apple-darwin22.4.0)\n",
      "  CPU: 8 × Apple M1\n",
      "  WORD_SIZE: 64\n",
      "  LIBM: libopenlibm\n",
      "  LLVM: libLLVM-15.0.7 (ORCJIT, apple-m1)\n",
      "Threads: 1 default, 0 interactive, 1 GC (on 4 virtual cores)\n",
      "Environment:\n",
      "  JULIA_NUM_THREADS = \n"
     ]
    }
   ],
   "source": [
    "# julia version\n",
    "versioninfo()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "# loading packages\n",
    "using Pkg\n",
    "using CSV\n",
    "using DataFrames\n",
    "using Downloads\n",
    "using Missings\n",
    "using Random\n",
    "using Statistics"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\u001b[36m\u001b[1mProject\u001b[22m\u001b[39m JuliaBasics v0.1.0\n",
      "\u001b[32m\u001b[1mStatus\u001b[22m\u001b[39m `~/Documents/Projects/Github/JuliaBasics/Project.toml`\n",
      "  \u001b[90m[336ed68f] \u001b[39mCSV v0.10.12\n",
      "  \u001b[90m[a93c6f00] \u001b[39mDataFrames v1.6.1\n",
      "  \u001b[90m[e1d29d7a] \u001b[39mMissings v1.1.0\n"
     ]
    }
   ],
   "source": [
    "# package versions\n",
    "Pkg.status()"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## download data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "# set directory\n",
    "data_dir = \"data\";"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "# create directory\n",
    "if !isdir(data_dir)\n",
    "    mkdir(data_dir)\n",
    "end;"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "# set file name and path\n",
    "file_name = \"iris.csv\"\n",
    "file_path = joinpath(pwd(), data_dir, file_name);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "# set file url\n",
    "file_url = string(\"https://raw.githubusercontent.com/mwaskom/seaborn-data/master/\", file_name);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\"/Users/rene/Documents/Projects/Github/JuliaBasics/data/iris.csv\""
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# download data\n",
    "if !isfile(file_path)\n",
    "    Downloads.download(file_url, file_path);\n",
    "end"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## read data"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [],
   "source": [
    "# read data\n",
    "iris = DataFrame(CSV.File(file_path, delim = \",\"));"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## explore data"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `nrow`, `ncol` and `size`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "150"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# number of rows\n",
    "nrow(iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# number of columns\n",
    "ncol(iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(150, 5)"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# size\n",
    "size(iris)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `names`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5-element Vector{String}:\n",
       " \"sepal_length\"\n",
       " \"sepal_width\"\n",
       " \"petal_length\"\n",
       " \"petal_width\"\n",
       " \"species\""
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# column names\n",
    "names(iris)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `propertynames`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5-element Vector{Symbol}:\n",
       " :sepal_length\n",
       " :sepal_width\n",
       " :petal_length\n",
       " :petal_width\n",
       " :species"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# column names\n",
    "propertynames(iris)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `eltype`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# element type\n",
    "eltype(iris.species)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5-element Vector{DataType}:\n",
       " Float64\n",
       " Float64\n",
       " Float64\n",
       " Float64\n",
       " String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# element types\n",
    "eltype.(eachcol(iris))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Dict{String, DataType} with 5 entries:\n",
       "  \"sepal_length\" => Float64\n",
       "  \"petal_width\"  => Float64\n",
       "  \"petal_length\" => Float64\n",
       "  \"sepal_width\"  => Float64\n",
       "  \"species\"      => String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# dict of element types\n",
    "Dict(names(iris) .=> eltype.(eachcol(iris)))"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `unique`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "3-element Vector{String15}:\n",
       " \"setosa\"\n",
       " \"versicolor\"\n",
       " \"virginica\""
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# unique values\n",
    "unique(iris.species)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### value counts"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>3×2 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">species</th><th style = \"text-align: left;\">nrow</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"String15\" style = \"text-align: left;\">String15</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">setosa</td><td style = \"text-align: right;\">50</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">versicolor</td><td style = \"text-align: right;\">50</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">50</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& species & nrow\\\\\n",
       "\t\\hline\n",
       "\t& String15 & Int64\\\\\n",
       "\t\\hline\n",
       "\t1 & setosa & 50 \\\\\n",
       "\t2 & versicolor & 50 \\\\\n",
       "\t3 & virginica & 50 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m3×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m species    \u001b[0m\u001b[1m nrow  \u001b[0m\n",
       "     │\u001b[90m String15   \u001b[0m\u001b[90m Int64 \u001b[0m\n",
       "─────┼───────────────────\n",
       "   1 │ setosa         50\n",
       "   2 │ versicolor     50\n",
       "   3 │ virginica      50"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# value counts\n",
    "combine(groupby(iris, :species), nrow)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `first`, `last`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">3.5</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.6</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 5.1 & 3.5 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 4.9 & 3.0 & 1.4 & 0.2 & setosa \\\\\n",
       "\t3 & 4.7 & 3.2 & 1.3 & 0.2 & setosa \\\\\n",
       "\t4 & 4.6 & 3.1 & 1.5 & 0.2 & setosa \\\\\n",
       "\t5 & 5.0 & 3.6 & 1.4 & 0.2 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼────────────────────────────────────────────────────────────────\n",
       "   1 │          5.1          3.5           1.4          0.2  setosa\n",
       "   2 │          4.9          3.0           1.4          0.2  setosa\n",
       "   3 │          4.7          3.2           1.3          0.2  setosa\n",
       "   4 │          4.6          3.1           1.5          0.2  setosa\n",
       "   5 │          5.0          3.6           1.4          0.2  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# first rows\n",
    "first(iris, 5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>3×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">6.5</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">5.2</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">6.2</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">5.9</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 6.5 & 3.0 & 5.2 & 2.0 & virginica \\\\\n",
       "\t2 & 6.2 & 3.4 & 5.4 & 2.3 & virginica \\\\\n",
       "\t3 & 5.9 & 3.0 & 5.1 & 1.8 & virginica \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m3×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species   \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15  \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────\n",
       "   1 │          6.5          3.0           5.2          2.0  virginica\n",
       "   2 │          6.2          3.4           5.4          2.3  virginica\n",
       "   3 │          5.9          3.0           5.1          1.8  virginica"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# last rows\n",
    "last(iris, 3)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `describe`"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### all columns"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"DataType\" style = \"text-align: left;\">DataType</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: left;\">5.84333</td><td style = \"text-align: left;\">4.3</td><td style = \"text-align: left;\">5.8</td><td style = \"text-align: left;\">7.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: left;\">3.05733</td><td style = \"text-align: left;\">2.0</td><td style = \"text-align: left;\">3.0</td><td style = \"text-align: left;\">4.4</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: left;\">3.758</td><td style = \"text-align: left;\">1.0</td><td style = \"text-align: left;\">4.35</td><td style = \"text-align: left;\">6.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: left;\">1.19933</td><td style = \"text-align: left;\">0.1</td><td style = \"text-align: left;\">1.3</td><td style = \"text-align: left;\">2.5</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">setosa</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Union… & Any & Union… & Any & Int64 & DataType\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 5.84333 & 4.3 & 5.8 & 7.9 & 0 & Float64 \\\\\n",
       "\t2 & sepal\\_width & 3.05733 & 2.0 & 3.0 & 4.4 & 0 & Float64 \\\\\n",
       "\t3 & petal\\_length & 3.758 & 1.0 & 4.35 & 6.9 & 0 & Float64 \\\\\n",
       "\t4 & petal\\_width & 1.19933 & 0.1 & 1.3 & 2.5 & 0 & Float64 \\\\\n",
       "\t5 & species &  & setosa &  & virginica & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min    \u001b[0m\u001b[1m median \u001b[0m\u001b[1m max       \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype   \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Union…  \u001b[0m\u001b[90m Any    \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Any       \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m DataType \u001b[0m\n",
       "─────┼──────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length  5.84333  4.3     5.8     7.9               0  Float64\n",
       "   2 │ sepal_width   3.05733  2.0     3.0     4.4               0  Float64\n",
       "   3 │ petal_length  3.758    1.0     4.35    6.9               0  Float64\n",
       "   4 │ petal_width   1.19933  0.1     1.3     2.5               0  Float64\n",
       "   5 │ species      \u001b[90m         \u001b[0m setosa \u001b[90m        \u001b[0m virginica         0  String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# all columns\n",
    "describe(iris)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### numeric columns"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>4×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"DataType\" style = \"text-align: left;\">DataType</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: right;\">5.84333</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">5.8</td><td style = \"text-align: right;\">7.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: right;\">3.05733</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: right;\">3.758</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">4.35</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: right;\">1.19933</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Float64 & Float64 & Float64 & Float64 & Int64 & DataType\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 5.84333 & 4.3 & 5.8 & 7.9 & 0 & Float64 \\\\\n",
       "\t2 & sepal\\_width & 3.05733 & 2.0 & 3.0 & 4.4 & 0 & Float64 \\\\\n",
       "\t3 & petal\\_length & 3.758 & 1.0 & 4.35 & 6.9 & 0 & Float64 \\\\\n",
       "\t4 & petal\\_width & 1.19933 & 0.1 & 1.3 & 2.5 & 0 & Float64 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m4×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min     \u001b[0m\u001b[1m median  \u001b[0m\u001b[1m max     \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype   \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m DataType \u001b[0m\n",
       "─────┼──────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length  5.84333      4.3     5.8       7.9         0  Float64\n",
       "   2 │ sepal_width   3.05733      2.0     3.0       4.4         0  Float64\n",
       "   3 │ petal_length  3.758        1.0     4.35      6.9         0  Float64\n",
       "   4 │ petal_width   1.19933      0.1     1.3       2.5         0  Float64"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# number\n",
    "describe(iris, cols=names(iris, Number))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>4×8 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">q25</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">q75</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">std</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">5.8</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">7.9</td><td style = \"text-align: right;\">5.84333</td><td style = \"text-align: right;\">0.828066</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">3.3</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">3.05733</td><td style = \"text-align: right;\">0.435866</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">1.6</td><td style = \"text-align: right;\">4.35</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">3.758</td><td style = \"text-align: right;\">1.7653</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">1.19933</td><td style = \"text-align: right;\">0.762238</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccccccc}\n",
       "\t& variable & min & q25 & median & q75 & max & mean & std\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Float64 & Float64 & Float64 & Float64 & Float64 & Float64 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 4.3 & 5.1 & 5.8 & 6.4 & 7.9 & 5.84333 & 0.828066 \\\\\n",
       "\t2 & sepal\\_width & 2.0 & 2.8 & 3.0 & 3.3 & 4.4 & 3.05733 & 0.435866 \\\\\n",
       "\t3 & petal\\_length & 1.0 & 1.6 & 4.35 & 5.1 & 6.9 & 3.758 & 1.7653 \\\\\n",
       "\t4 & petal\\_width & 0.1 & 0.3 & 1.3 & 1.8 & 2.5 & 1.19933 & 0.762238 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m4×8 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m min     \u001b[0m\u001b[1m q25     \u001b[0m\u001b[1m median  \u001b[0m\u001b[1m q75     \u001b[0m\u001b[1m max     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m std\u001b[0m ⋯\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Flo\u001b[0m ⋯\n",
       "─────┼──────────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length      4.3      5.1     5.8       6.4      7.9  5.84333  0.8 ⋯\n",
       "   2 │ sepal_width       2.0      2.8     3.0       3.3      4.4  3.05733  0.4\n",
       "   3 │ petal_length      1.0      1.6     4.35      5.1      6.9  3.758    1.7\n",
       "   4 │ petal_width       0.1      0.3     1.3       1.8      2.5  1.19933  0.7\n",
       "\u001b[36m                                                                1 column omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# statistics\n",
    "describe(iris, cols=names(iris, Number), :min, :q25, :median, :q75, :max, :mean, :std)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>4×4 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">range</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">7.9</td><td style = \"text-align: right;\">3.6</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">2.4</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">5.9</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">2.4</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccc}\n",
       "\t& variable & min & max & range\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Float64 & Float64 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 4.3 & 7.9 & 3.6 \\\\\n",
       "\t2 & sepal\\_width & 2.0 & 4.4 & 2.4 \\\\\n",
       "\t3 & petal\\_length & 1.0 & 6.9 & 5.9 \\\\\n",
       "\t4 & petal\\_width & 0.1 & 2.5 & 2.4 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m4×4 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m min     \u001b[0m\u001b[1m max     \u001b[0m\u001b[1m range   \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\n",
       "─────┼─────────────────────────────────────────\n",
       "   1 │ sepal_length      4.3      7.9      3.6\n",
       "   2 │ sepal_width       2.0      4.4      2.4\n",
       "   3 │ petal_length      1.0      6.9      5.9\n",
       "   4 │ petal_width       0.1      2.5      2.4"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# statistics, adding an anonymous function\n",
    "describe(iris, cols=names(iris, Number), :min, :max, (x -> maximum(x) - minimum(x)) => :range)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>4×4 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">range</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">7.9</td><td style = \"text-align: right;\">3.6</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">2.4</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">5.9</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">2.4</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccc}\n",
       "\t& variable & min & max & range\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Float64 & Float64 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 4.3 & 7.9 & 3.6 \\\\\n",
       "\t2 & sepal\\_width & 2.0 & 4.4 & 2.4 \\\\\n",
       "\t3 & petal\\_length & 1.0 & 6.9 & 5.9 \\\\\n",
       "\t4 & petal\\_width & 0.1 & 2.5 & 2.4 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m4×4 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m min     \u001b[0m\u001b[1m max     \u001b[0m\u001b[1m range   \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\n",
       "─────┼─────────────────────────────────────────\n",
       "   1 │ sepal_length      4.3      7.9      3.6\n",
       "   2 │ sepal_width       2.0      4.4      2.4\n",
       "   3 │ petal_length      1.0      6.9      5.9\n",
       "   4 │ petal_width       0.1      2.5      2.4"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# statistics, adding a function\n",
    "\n",
    "function my_function(x)\n",
    "    range = maximum(x) - minimum(x)\n",
    "    return range\n",
    "end\n",
    "\n",
    "describe(iris, cols=names(iris, Number), :min, :max, my_function => :range)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### alphanumeric columns"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>1×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Nothing\" style = \"text-align: left;\">Nothing</th><th title = \"String15\" style = \"text-align: left;\">String15</th><th title = \"Nothing\" style = \"text-align: left;\">Nothing</th><th title = \"String15\" style = \"text-align: left;\">String15</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"DataType\" style = \"text-align: left;\">DataType</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">species</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">setosa</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Nothing & String15 & Nothing & String15 & Int64 & DataType\\\\\n",
       "\t\\hline\n",
       "\t1 & species &  & setosa &  & virginica & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m1×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min      \u001b[0m\u001b[1m median  \u001b[0m\u001b[1m max       \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype   \u001b[0m\n",
       "     │\u001b[90m Symbol   \u001b[0m\u001b[90m Nothing \u001b[0m\u001b[90m String15 \u001b[0m\u001b[90m Nothing \u001b[0m\u001b[90m String15  \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m DataType \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────────\n",
       "   1 │ species  \u001b[90m         \u001b[0m setosa   \u001b[90m         \u001b[0m virginica         0  String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# abstractstring\n",
    "describe(iris, cols=names(iris, AbstractString))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>1×6 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">first</th><th style = \"text-align: left;\">last</th><th style = \"text-align: left;\">nunique</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">nnonmissing</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"String15\" style = \"text-align: left;\">String15</th><th title = \"String15\" style = \"text-align: left;\">String15</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">species</td><td style = \"text-align: left;\">setosa</td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">3</td><td style = \"text-align: right;\">0</td><td style = \"text-align: right;\">150</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccccc}\n",
       "\t& variable & first & last & nunique & nmissing & nnonmissing\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & String15 & String15 & Int64 & Int64 & Int64\\\\\n",
       "\t\\hline\n",
       "\t1 & species & setosa & virginica & 3 & 0 & 150 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m1×6 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable \u001b[0m\u001b[1m first    \u001b[0m\u001b[1m last      \u001b[0m\u001b[1m nunique \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m nnonmissing \u001b[0m\n",
       "     │\u001b[90m Symbol   \u001b[0m\u001b[90m String15 \u001b[0m\u001b[90m String15  \u001b[0m\u001b[90m Int64   \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m Int64       \u001b[0m\n",
       "─────┼───────────────────────────────────────────────────────────────\n",
       "   1 │ species   setosa    virginica        3         0          150"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# statistics\n",
    "describe(iris, cols=names(iris, AbstractString), :first, :last, :nunique, :nmissing, :nnonmissing)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>1×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">min_length</th><th style = \"text-align: left;\">max_length</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">species</td><td style = \"text-align: right;\">6</td><td style = \"text-align: right;\">10</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& variable & min\\_length & max\\_length\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Int64 & Int64\\\\\n",
       "\t\\hline\n",
       "\t1 & species & 6 & 10 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m1×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable \u001b[0m\u001b[1m min_length \u001b[0m\u001b[1m max_length \u001b[0m\n",
       "     │\u001b[90m Symbol   \u001b[0m\u001b[90m Int64      \u001b[0m\u001b[90m Int64      \u001b[0m\n",
       "─────┼──────────────────────────────────\n",
       "   1 │ species            6          10"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# statistics, adding anonymous functions\n",
    "describe(\n",
    "    iris, \n",
    "    cols=names(iris, AbstractString), \n",
    "    (x -> minimum(length.(x))) => :min_length, \n",
    "    (x -> maximum(length.(x))) => :max_length\n",
    ")"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### selected columns"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>3×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"DataType\" style = \"text-align: left;\">DataType</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: right;\">5.84333</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">5.8</td><td style = \"text-align: right;\">7.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: right;\">3.05733</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: right;\">3.758</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">4.35</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Float64 & Float64 & Float64 & Float64 & Int64 & DataType\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 5.84333 & 4.3 & 5.8 & 7.9 & 0 & Float64 \\\\\n",
       "\t2 & sepal\\_width & 3.05733 & 2.0 & 3.0 & 4.4 & 0 & Float64 \\\\\n",
       "\t3 & petal\\_length & 3.758 & 1.0 & 4.35 & 6.9 & 0 & Float64 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m3×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min     \u001b[0m\u001b[1m median  \u001b[0m\u001b[1m max     \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype   \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m DataType \u001b[0m\n",
       "─────┼──────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length  5.84333      4.3     5.8       7.9         0  Float64\n",
       "   2 │ sepal_width   3.05733      2.0     3.0       4.4         0  Float64\n",
       "   3 │ petal_length  3.758        1.0     4.35      6.9         0  Float64"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# range\n",
    "describe(iris, cols=1:3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>3×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"DataType\" style = \"text-align: left;\">DataType</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: left;\">5.84333</td><td style = \"text-align: left;\">4.3</td><td style = \"text-align: left;\">5.8</td><td style = \"text-align: left;\">7.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: left;\">3.05733</td><td style = \"text-align: left;\">2.0</td><td style = \"text-align: left;\">3.0</td><td style = \"text-align: left;\">4.4</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">species</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">setosa</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Union… & Any & Union… & Any & Int64 & DataType\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 5.84333 & 4.3 & 5.8 & 7.9 & 0 & Float64 \\\\\n",
       "\t2 & sepal\\_width & 3.05733 & 2.0 & 3.0 & 4.4 & 0 & Float64 \\\\\n",
       "\t3 & species &  & setosa &  & virginica & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m3×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min    \u001b[0m\u001b[1m median \u001b[0m\u001b[1m max       \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype   \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Union…  \u001b[0m\u001b[90m Any    \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Any       \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m DataType \u001b[0m\n",
       "─────┼──────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length  5.84333  4.3     5.8     7.9               0  Float64\n",
       "   2 │ sepal_width   3.05733  2.0     3.0     4.4               0  Float64\n",
       "   3 │ species      \u001b[90m         \u001b[0m setosa \u001b[90m        \u001b[0m virginica         0  String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# index\n",
    "describe(iris, cols=[1, 2, 5])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>2×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"DataType\" style = \"text-align: left;\">DataType</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: right;\">3.758</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">4.35</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: right;\">1.19933</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Float64 & Float64 & Float64 & Float64 & Int64 & DataType\\\\\n",
       "\t\\hline\n",
       "\t1 & petal\\_length & 3.758 & 1.0 & 4.35 & 6.9 & 0 & Float64 \\\\\n",
       "\t2 & petal\\_width & 1.19933 & 0.1 & 1.3 & 2.5 & 0 & Float64 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m2×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min     \u001b[0m\u001b[1m median  \u001b[0m\u001b[1m max     \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype   \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m DataType \u001b[0m\n",
       "─────┼──────────────────────────────────────────────────────────────────────\n",
       "   1 │ petal_length  3.758        1.0     4.35      6.9         0  Float64\n",
       "   2 │ petal_width   1.19933      0.1     1.3       2.5         0  Float64"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# propertynames\n",
    "describe(iris, cols=[:petal_length, :petal_width])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>2×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"DataType\" style = \"text-align: left;\">DataType</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: right;\">3.05733</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: right;\">1.19933</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Float64 & Float64 & Float64 & Float64 & Int64 & DataType\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_width & 3.05733 & 2.0 & 3.0 & 4.4 & 0 & Float64 \\\\\n",
       "\t2 & petal\\_width & 1.19933 & 0.1 & 1.3 & 2.5 & 0 & Float64 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m2×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable    \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min     \u001b[0m\u001b[1m median  \u001b[0m\u001b[1m max     \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype   \u001b[0m\n",
       "     │\u001b[90m Symbol      \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m DataType \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_width  3.05733      2.0      3.0      4.4         0  Float64\n",
       "   2 │ petal_width  1.19933      0.1      1.3      2.5         0  Float64"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# regex\n",
    "describe(iris, cols=r\"width\")"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### selected values"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 34,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"DataType\" style = \"text-align: left;\">DataType</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: left;\">5.006</td><td style = \"text-align: left;\">4.3</td><td style = \"text-align: left;\">5.0</td><td style = \"text-align: left;\">5.8</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: left;\">3.428</td><td style = \"text-align: left;\">2.3</td><td style = \"text-align: left;\">3.4</td><td style = \"text-align: left;\">4.4</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: left;\">1.462</td><td style = \"text-align: left;\">1.0</td><td style = \"text-align: left;\">1.5</td><td style = \"text-align: left;\">1.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: left;\">0.246</td><td style = \"text-align: left;\">0.1</td><td style = \"text-align: left;\">0.2</td><td style = \"text-align: left;\">0.6</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">setosa</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">setosa</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Union… & Any & Union… & Any & Int64 & DataType\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 5.006 & 4.3 & 5.0 & 5.8 & 0 & Float64 \\\\\n",
       "\t2 & sepal\\_width & 3.428 & 2.3 & 3.4 & 4.4 & 0 & Float64 \\\\\n",
       "\t3 & petal\\_length & 1.462 & 1.0 & 1.5 & 1.9 & 0 & Float64 \\\\\n",
       "\t4 & petal\\_width & 0.246 & 0.1 & 0.2 & 0.6 & 0 & Float64 \\\\\n",
       "\t5 & species &  & setosa &  & setosa & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean   \u001b[0m\u001b[1m min    \u001b[0m\u001b[1m median \u001b[0m\u001b[1m max    \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype   \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Any    \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Any    \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m DataType \u001b[0m\n",
       "─────┼──────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length  5.006   4.3     5.0     5.8            0  Float64\n",
       "   2 │ sepal_width   3.428   2.3     3.4     4.4            0  Float64\n",
       "   3 │ petal_length  1.462   1.0     1.5     1.9            0  Float64\n",
       "   4 │ petal_width   0.246   0.1     0.2     0.6            0  Float64\n",
       "   5 │ species      \u001b[90m        \u001b[0m setosa \u001b[90m        \u001b[0m setosa         0  String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# setosa\n",
    "describe(iris[iris.species .== \"setosa\", :])"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Subsetting data"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### rows"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"DataType\" style = \"text-align: left;\">DataType</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: left;\">5.84333</td><td style = \"text-align: left;\">4.3</td><td style = \"text-align: left;\">5.8</td><td style = \"text-align: left;\">7.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: left;\">3.05733</td><td style = \"text-align: left;\">2.0</td><td style = \"text-align: left;\">3.0</td><td style = \"text-align: left;\">4.4</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: left;\">3.758</td><td style = \"text-align: left;\">1.0</td><td style = \"text-align: left;\">4.35</td><td style = \"text-align: left;\">6.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: left;\">1.19933</td><td style = \"text-align: left;\">0.1</td><td style = \"text-align: left;\">1.3</td><td style = \"text-align: left;\">2.5</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">setosa</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Union… & Any & Union… & Any & Int64 & DataType\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 5.84333 & 4.3 & 5.8 & 7.9 & 0 & Float64 \\\\\n",
       "\t2 & sepal\\_width & 3.05733 & 2.0 & 3.0 & 4.4 & 0 & Float64 \\\\\n",
       "\t3 & petal\\_length & 3.758 & 1.0 & 4.35 & 6.9 & 0 & Float64 \\\\\n",
       "\t4 & petal\\_width & 1.19933 & 0.1 & 1.3 & 2.5 & 0 & Float64 \\\\\n",
       "\t5 & species &  & setosa &  & virginica & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min    \u001b[0m\u001b[1m median \u001b[0m\u001b[1m max       \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype   \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Union…  \u001b[0m\u001b[90m Any    \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Any       \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m DataType \u001b[0m\n",
       "─────┼──────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length  5.84333  4.3     5.8     7.9               0  Float64\n",
       "   2 │ sepal_width   3.05733  2.0     3.0     4.4               0  Float64\n",
       "   3 │ petal_length  3.758    1.0     4.35    6.9               0  Float64\n",
       "   4 │ petal_width   1.19933  0.1     1.3     2.5               0  Float64\n",
       "   5 │ species      \u001b[90m         \u001b[0m setosa \u001b[90m        \u001b[0m virginica         0  String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# describe\n",
    "describe(iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 36,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>6×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.6</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">3.9</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 5.0 & 3.6 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 5.4 & 3.9 & 1.7 & 0.4 & setosa \\\\\n",
       "\t3 & 4.6 & 3.4 & 1.4 & 0.3 & setosa \\\\\n",
       "\t4 & 5.0 & 3.4 & 1.5 & 0.2 & setosa \\\\\n",
       "\t5 & 4.4 & 2.9 & 1.4 & 0.2 & setosa \\\\\n",
       "\t6 & 4.9 & 3.1 & 1.5 & 0.1 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m6×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼────────────────────────────────────────────────────────────────\n",
       "   1 │          5.0          3.6           1.4          0.2  setosa\n",
       "   2 │          5.4          3.9           1.7          0.4  setosa\n",
       "   3 │          4.6          3.4           1.4          0.3  setosa\n",
       "   4 │          5.0          3.4           1.5          0.2  setosa\n",
       "   5 │          4.4          2.9           1.4          0.2  setosa\n",
       "   6 │          4.9          3.1           1.5          0.1  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# select rows\n",
    "iris[5:10, :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">6.2</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.1</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">5.7</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.1</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">3.3</td><td style = \"text-align: right;\">6.0</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">5.8</td><td style = \"text-align: right;\">2.7</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 6.2 & 2.9 & 4.3 & 1.3 & versicolor \\\\\n",
       "\t2 & 5.1 & 2.5 & 3.0 & 1.1 & versicolor \\\\\n",
       "\t3 & 5.7 & 2.8 & 4.1 & 1.3 & versicolor \\\\\n",
       "\t4 & 6.3 & 3.3 & 6.0 & 2.5 & virginica \\\\\n",
       "\t5 & 5.8 & 2.7 & 5.1 & 1.9 & virginica \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species    \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15   \u001b[0m\n",
       "─────┼──────────────────────────────────────────────────────────────────\n",
       "   1 │          6.2          2.9           4.3          1.3  versicolor\n",
       "   2 │          5.1          2.5           3.0          1.1  versicolor\n",
       "   3 │          5.7          2.8           4.1          1.3  versicolor\n",
       "   4 │          6.3          3.3           6.0          2.5  virginica\n",
       "   5 │          5.8          2.7           5.1          1.9  virginica"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# select rows\n",
    "iris[end-52:end-48, :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 38,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "150-element BitVector:\n",
       " 0\n",
       " 0\n",
       " 1\n",
       " 1\n",
       " 0\n",
       " 0\n",
       " 1\n",
       " 0\n",
       " 1\n",
       " 0\n",
       " ⋮\n",
       " 0\n",
       " 0\n",
       " 0\n",
       " 0\n",
       " 0\n",
       " 0\n",
       " 0\n",
       " 0\n",
       " 0"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# bitvector\n",
    "iris.sepal_length .< 4.8"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 39,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>11×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.1</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.6</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.6</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">4.5</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">11</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 4.7 & 3.2 & 1.3 & 0.2 & setosa \\\\\n",
       "\t2 & 4.6 & 3.1 & 1.5 & 0.2 & setosa \\\\\n",
       "\t3 & 4.6 & 3.4 & 1.4 & 0.3 & setosa \\\\\n",
       "\t4 & 4.4 & 2.9 & 1.4 & 0.2 & setosa \\\\\n",
       "\t5 & 4.3 & 3.0 & 1.1 & 0.1 & setosa \\\\\n",
       "\t6 & 4.6 & 3.6 & 1.0 & 0.2 & setosa \\\\\n",
       "\t7 & 4.7 & 3.2 & 1.6 & 0.2 & setosa \\\\\n",
       "\t8 & 4.4 & 3.0 & 1.3 & 0.2 & setosa \\\\\n",
       "\t9 & 4.5 & 2.3 & 1.3 & 0.3 & setosa \\\\\n",
       "\t10 & 4.4 & 3.2 & 1.3 & 0.2 & setosa \\\\\n",
       "\t11 & 4.6 & 3.2 & 1.4 & 0.2 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m11×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼────────────────────────────────────────────────────────────────\n",
       "   1 │          4.7          3.2           1.3          0.2  setosa\n",
       "   2 │          4.6          3.1           1.5          0.2  setosa\n",
       "   3 │          4.6          3.4           1.4          0.3  setosa\n",
       "   4 │          4.4          2.9           1.4          0.2  setosa\n",
       "   5 │          4.3          3.0           1.1          0.1  setosa\n",
       "   6 │          4.6          3.6           1.0          0.2  setosa\n",
       "   7 │          4.7          3.2           1.6          0.2  setosa\n",
       "   8 │          4.4          3.0           1.3          0.2  setosa\n",
       "   9 │          4.5          2.3           1.3          0.3  setosa\n",
       "  10 │          4.4          3.2           1.3          0.2  setosa\n",
       "  11 │          4.6          3.2           1.4          0.2  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# subset\n",
    "iris[iris.sepal_length .< 4.8, :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 40,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>6×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.6</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.6</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 4.7 & 3.2 & 1.3 & 0.2 & setosa \\\\\n",
       "\t2 & 4.6 & 3.1 & 1.5 & 0.2 & setosa \\\\\n",
       "\t3 & 4.6 & 3.4 & 1.4 & 0.3 & setosa \\\\\n",
       "\t4 & 4.6 & 3.6 & 1.0 & 0.2 & setosa \\\\\n",
       "\t5 & 4.7 & 3.2 & 1.6 & 0.2 & setosa \\\\\n",
       "\t6 & 4.6 & 3.2 & 1.4 & 0.2 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m6×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼────────────────────────────────────────────────────────────────\n",
       "   1 │          4.7          3.2           1.3          0.2  setosa\n",
       "   2 │          4.6          3.1           1.5          0.2  setosa\n",
       "   3 │          4.6          3.4           1.4          0.3  setosa\n",
       "   4 │          4.6          3.6           1.0          0.2  setosa\n",
       "   5 │          4.7          3.2           1.6          0.2  setosa\n",
       "   6 │          4.6          3.2           1.4          0.2  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# subset\n",
    "iris[(iris.sepal_length .> 4.5) .&& (iris.sepal_length .< 4.8), :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 41,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>6×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.6</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.6</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 4.7 & 3.2 & 1.3 & 0.2 & setosa \\\\\n",
       "\t2 & 4.6 & 3.1 & 1.5 & 0.2 & setosa \\\\\n",
       "\t3 & 4.6 & 3.4 & 1.4 & 0.3 & setosa \\\\\n",
       "\t4 & 4.6 & 3.6 & 1.0 & 0.2 & setosa \\\\\n",
       "\t5 & 4.7 & 3.2 & 1.6 & 0.2 & setosa \\\\\n",
       "\t6 & 4.6 & 3.2 & 1.4 & 0.2 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m6×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼────────────────────────────────────────────────────────────────\n",
       "   1 │          4.7          3.2           1.3          0.2  setosa\n",
       "   2 │          4.6          3.1           1.5          0.2  setosa\n",
       "   3 │          4.6          3.4           1.4          0.3  setosa\n",
       "   4 │          4.6          3.6           1.0          0.2  setosa\n",
       "   5 │          4.7          3.2           1.6          0.2  setosa\n",
       "   6 │          4.6          3.2           1.4          0.2  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# bitwise and\n",
    "iris[.&(iris.sepal_length .> 4.5, iris.sepal_length .< 4.8), :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 42,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>10×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.1</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">7.6</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">6.6</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">3.8</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.2</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.6</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">7.9</td><td style = \"text-align: right;\">3.8</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 4.4 & 2.9 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 4.3 & 3.0 & 1.1 & 0.1 & setosa \\\\\n",
       "\t3 & 4.4 & 3.0 & 1.3 & 0.2 & setosa \\\\\n",
       "\t4 & 4.4 & 3.2 & 1.3 & 0.2 & setosa \\\\\n",
       "\t5 & 7.6 & 3.0 & 6.6 & 2.1 & virginica \\\\\n",
       "\t6 & 7.7 & 3.8 & 6.7 & 2.2 & virginica \\\\\n",
       "\t7 & 7.7 & 2.6 & 6.9 & 2.3 & virginica \\\\\n",
       "\t8 & 7.7 & 2.8 & 6.7 & 2.0 & virginica \\\\\n",
       "\t9 & 7.9 & 3.8 & 6.4 & 2.0 & virginica \\\\\n",
       "\t10 & 7.7 & 3.0 & 6.1 & 2.3 & virginica \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m10×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species   \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15  \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────\n",
       "   1 │          4.4          2.9           1.4          0.2  setosa\n",
       "   2 │          4.3          3.0           1.1          0.1  setosa\n",
       "   3 │          4.4          3.0           1.3          0.2  setosa\n",
       "   4 │          4.4          3.2           1.3          0.2  setosa\n",
       "   5 │          7.6          3.0           6.6          2.1  virginica\n",
       "   6 │          7.7          3.8           6.7          2.2  virginica\n",
       "   7 │          7.7          2.6           6.9          2.3  virginica\n",
       "   8 │          7.7          2.8           6.7          2.0  virginica\n",
       "   9 │          7.9          3.8           6.4          2.0  virginica\n",
       "  10 │          7.7          3.0           6.1          2.3  virginica"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# subset\n",
    "iris[(iris.sepal_length .< 4.5 ) .|| (iris.sepal_length .> 7.5), :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 43,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>10×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.1</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">7.6</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">6.6</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">3.8</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.2</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.6</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">7.9</td><td style = \"text-align: right;\">3.8</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 4.4 & 2.9 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 4.3 & 3.0 & 1.1 & 0.1 & setosa \\\\\n",
       "\t3 & 4.4 & 3.0 & 1.3 & 0.2 & setosa \\\\\n",
       "\t4 & 4.4 & 3.2 & 1.3 & 0.2 & setosa \\\\\n",
       "\t5 & 7.6 & 3.0 & 6.6 & 2.1 & virginica \\\\\n",
       "\t6 & 7.7 & 3.8 & 6.7 & 2.2 & virginica \\\\\n",
       "\t7 & 7.7 & 2.6 & 6.9 & 2.3 & virginica \\\\\n",
       "\t8 & 7.7 & 2.8 & 6.7 & 2.0 & virginica \\\\\n",
       "\t9 & 7.9 & 3.8 & 6.4 & 2.0 & virginica \\\\\n",
       "\t10 & 7.7 & 3.0 & 6.1 & 2.3 & virginica \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m10×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species   \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15  \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────\n",
       "   1 │          4.4          2.9           1.4          0.2  setosa\n",
       "   2 │          4.3          3.0           1.1          0.1  setosa\n",
       "   3 │          4.4          3.0           1.3          0.2  setosa\n",
       "   4 │          4.4          3.2           1.3          0.2  setosa\n",
       "   5 │          7.6          3.0           6.6          2.1  virginica\n",
       "   6 │          7.7          3.8           6.7          2.2  virginica\n",
       "   7 │          7.7          2.6           6.9          2.3  virginica\n",
       "   8 │          7.7          2.8           6.7          2.0  virginica\n",
       "   9 │          7.9          3.8           6.4          2.0  virginica\n",
       "  10 │          7.7          3.0           6.1          2.3  virginica"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# bitwise or\n",
    "iris[.|(iris.sepal_length .< 4.5, iris.sepal_length .> 7.5), :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 44,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>6×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">7.6</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">6.6</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">3.8</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.2</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.6</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">7.9</td><td style = \"text-align: right;\">3.8</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 7.6 & 3.0 & 6.6 & 2.1 & virginica \\\\\n",
       "\t2 & 7.7 & 3.8 & 6.7 & 2.2 & virginica \\\\\n",
       "\t3 & 7.7 & 2.6 & 6.9 & 2.3 & virginica \\\\\n",
       "\t4 & 7.7 & 2.8 & 6.7 & 2.0 & virginica \\\\\n",
       "\t5 & 7.9 & 3.8 & 6.4 & 2.0 & virginica \\\\\n",
       "\t6 & 7.7 & 3.0 & 6.1 & 2.3 & virginica \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m6×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species   \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15  \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────\n",
       "   1 │          7.6          3.0           6.6          2.1  virginica\n",
       "   2 │          7.7          3.8           6.7          2.2  virginica\n",
       "   3 │          7.7          2.6           6.9          2.3  virginica\n",
       "   4 │          7.7          2.8           6.7          2.0  virginica\n",
       "   5 │          7.9          3.8           6.4          2.0  virginica\n",
       "   6 │          7.7          3.0           6.1          2.3  virginica"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# filter\n",
    "filter(row -> row.sepal_length > 7.5, iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 45,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>6×5 SubDataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">7.6</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">6.6</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">3.8</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.2</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.6</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">7.9</td><td style = \"text-align: right;\">3.8</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 7.6 & 3.0 & 6.6 & 2.1 & virginica \\\\\n",
       "\t2 & 7.7 & 3.8 & 6.7 & 2.2 & virginica \\\\\n",
       "\t3 & 7.7 & 2.6 & 6.9 & 2.3 & virginica \\\\\n",
       "\t4 & 7.7 & 2.8 & 6.7 & 2.0 & virginica \\\\\n",
       "\t5 & 7.9 & 3.8 & 6.4 & 2.0 & virginica \\\\\n",
       "\t6 & 7.7 & 3.0 & 6.1 & 2.3 & virginica \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m6×5 SubDataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species   \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15  \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────\n",
       "   1 │          7.6          3.0           6.6          2.1  virginica\n",
       "   2 │          7.7          3.8           6.7          2.2  virginica\n",
       "   3 │          7.7          2.6           6.9          2.3  virginica\n",
       "   4 │          7.7          2.8           6.7          2.0  virginica\n",
       "   5 │          7.9          3.8           6.4          2.0  virginica\n",
       "   6 │          7.7          3.0           6.1          2.3  virginica"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# filter (subset dataframe)\n",
    "filter(row -> row.sepal_length > 7.5, iris, view=true)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 46,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>25×5 SubDataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">6.5</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">6.6</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">6.2</td><td style = \"text-align: right;\">2.2</td><td style = \"text-align: right;\">4.5</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.0</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">1.2</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">6.8</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">11</td><td style = \"text-align: right;\">6.2</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: left;\">versicolor</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">12</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">13</td><td style = \"text-align: right;\">7.3</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">14</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">5.8</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">15</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.7</td><td style = \"text-align: right;\">5.3</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">16</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.6</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">17</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">18</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.7</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">19</td><td style = \"text-align: right;\">6.2</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">20</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">21</td><td style = \"text-align: right;\">7.4</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">22</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.2</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">23</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">24</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">2.6</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">25</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 6.5 & 2.8 & 4.6 & 1.5 & versicolor \\\\\n",
       "\t2 & 6.6 & 2.9 & 4.6 & 1.3 & versicolor \\\\\n",
       "\t3 & 6.1 & 2.9 & 4.7 & 1.4 & versicolor \\\\\n",
       "\t4 & 6.2 & 2.2 & 4.5 & 1.5 & versicolor \\\\\n",
       "\t5 & 6.1 & 2.8 & 4.0 & 1.3 & versicolor \\\\\n",
       "\t6 & 6.3 & 2.5 & 4.9 & 1.5 & versicolor \\\\\n",
       "\t7 & 6.1 & 2.8 & 4.7 & 1.2 & versicolor \\\\\n",
       "\t8 & 6.4 & 2.9 & 4.3 & 1.3 & versicolor \\\\\n",
       "\t9 & 6.8 & 2.8 & 4.8 & 1.4 & versicolor \\\\\n",
       "\t10 & 6.3 & 2.3 & 4.4 & 1.3 & versicolor \\\\\n",
       "\t11 & 6.2 & 2.9 & 4.3 & 1.3 & versicolor \\\\\n",
       "\t12 & 6.3 & 2.9 & 5.6 & 1.8 & virginica \\\\\n",
       "\t13 & 7.3 & 2.9 & 6.3 & 1.8 & virginica \\\\\n",
       "\t14 & 6.7 & 2.5 & 5.8 & 1.8 & virginica \\\\\n",
       "\t15 & 6.4 & 2.7 & 5.3 & 1.9 & virginica \\\\\n",
       "\t16 & 7.7 & 2.6 & 6.9 & 2.3 & virginica \\\\\n",
       "\t17 & 7.7 & 2.8 & 6.7 & 2.0 & virginica \\\\\n",
       "\t18 & 6.3 & 2.7 & 4.9 & 1.8 & virginica \\\\\n",
       "\t19 & 6.2 & 2.8 & 4.8 & 1.8 & virginica \\\\\n",
       "\t20 & 6.4 & 2.8 & 5.6 & 2.1 & virginica \\\\\n",
       "\t21 & 7.4 & 2.8 & 6.1 & 1.9 & virginica \\\\\n",
       "\t22 & 6.4 & 2.8 & 5.6 & 2.2 & virginica \\\\\n",
       "\t23 & 6.3 & 2.8 & 5.1 & 1.5 & virginica \\\\\n",
       "\t24 & 6.1 & 2.6 & 5.6 & 1.4 & virginica \\\\\n",
       "\t$\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m25×5 SubDataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species    \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15   \u001b[0m\n",
       "─────┼──────────────────────────────────────────────────────────────────\n",
       "   1 │          6.5          2.8           4.6          1.5  versicolor\n",
       "   2 │          6.6          2.9           4.6          1.3  versicolor\n",
       "   3 │          6.1          2.9           4.7          1.4  versicolor\n",
       "   4 │          6.2          2.2           4.5          1.5  versicolor\n",
       "   5 │          6.1          2.8           4.0          1.3  versicolor\n",
       "   6 │          6.3          2.5           4.9          1.5  versicolor\n",
       "   7 │          6.1          2.8           4.7          1.2  versicolor\n",
       "   8 │          6.4          2.9           4.3          1.3  versicolor\n",
       "  ⋮  │      ⋮             ⋮            ⋮             ⋮           ⋮\n",
       "  19 │          6.2          2.8           4.8          1.8  virginica\n",
       "  20 │          6.4          2.8           5.6          2.1  virginica\n",
       "  21 │          7.4          2.8           6.1          1.9  virginica\n",
       "  22 │          6.4          2.8           5.6          2.2  virginica\n",
       "  23 │          6.3          2.8           5.1          1.5  virginica\n",
       "  24 │          6.1          2.6           5.6          1.4  virginica\n",
       "  25 │          6.3          2.5           5.0          1.9  virginica\n",
       "\u001b[36m                                                         10 rows omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# filter (subset dataframe)\n",
    "filter(row -> row.sepal_length > 6 && row.sepal_width < 3, iris, view=true)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 47,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>14×5 SubDataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">7.3</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">5.8</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.7</td><td style = \"text-align: right;\">5.3</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.6</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">7.7</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.7</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">6.2</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">7.4</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">11</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.2</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">12</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">13</td><td style = \"text-align: right;\">6.1</td><td style = \"text-align: right;\">2.6</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">14</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 6.3 & 2.9 & 5.6 & 1.8 & virginica \\\\\n",
       "\t2 & 7.3 & 2.9 & 6.3 & 1.8 & virginica \\\\\n",
       "\t3 & 6.7 & 2.5 & 5.8 & 1.8 & virginica \\\\\n",
       "\t4 & 6.4 & 2.7 & 5.3 & 1.9 & virginica \\\\\n",
       "\t5 & 7.7 & 2.6 & 6.9 & 2.3 & virginica \\\\\n",
       "\t6 & 7.7 & 2.8 & 6.7 & 2.0 & virginica \\\\\n",
       "\t7 & 6.3 & 2.7 & 4.9 & 1.8 & virginica \\\\\n",
       "\t8 & 6.2 & 2.8 & 4.8 & 1.8 & virginica \\\\\n",
       "\t9 & 6.4 & 2.8 & 5.6 & 2.1 & virginica \\\\\n",
       "\t10 & 7.4 & 2.8 & 6.1 & 1.9 & virginica \\\\\n",
       "\t11 & 6.4 & 2.8 & 5.6 & 2.2 & virginica \\\\\n",
       "\t12 & 6.3 & 2.8 & 5.1 & 1.5 & virginica \\\\\n",
       "\t13 & 6.1 & 2.6 & 5.6 & 1.4 & virginica \\\\\n",
       "\t14 & 6.3 & 2.5 & 5.0 & 1.9 & virginica \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m14×5 SubDataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species   \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15  \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────\n",
       "   1 │          6.3          2.9           5.6          1.8  virginica\n",
       "   2 │          7.3          2.9           6.3          1.8  virginica\n",
       "   3 │          6.7          2.5           5.8          1.8  virginica\n",
       "   4 │          6.4          2.7           5.3          1.9  virginica\n",
       "   5 │          7.7          2.6           6.9          2.3  virginica\n",
       "   6 │          7.7          2.8           6.7          2.0  virginica\n",
       "   7 │          6.3          2.7           4.9          1.8  virginica\n",
       "   8 │          6.2          2.8           4.8          1.8  virginica\n",
       "   9 │          6.4          2.8           5.6          2.1  virginica\n",
       "  10 │          7.4          2.8           6.1          1.9  virginica\n",
       "  11 │          6.4          2.8           5.6          2.2  virginica\n",
       "  12 │          6.3          2.8           5.1          1.5  virginica\n",
       "  13 │          6.1          2.6           5.6          1.4  virginica\n",
       "  14 │          6.3          2.5           5.0          1.9  virginica"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# filter (subset dataframe)\n",
    "filter(row -> row.sepal_length > 6 && row.sepal_width < 3 && row.species == \"virginica\", iris, view=true)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 48,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "150-element BitVector:\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " ⋮\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# in\n",
    "in.(iris.species, Ref([\"virginica\", \"setosa\"]))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 49,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>100×5 DataFrame</span></div><div style = \"float: right;\"><span style = \"font-style: italic;\">75 rows omitted</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">3.5</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.6</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">3.9</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">2.9</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">11</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">3.7</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">12</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.6</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">13</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">89</td><td style = \"text-align: right;\">6.0</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">90</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">91</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.4</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">92</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">93</td><td style = \"text-align: right;\">5.8</td><td style = \"text-align: right;\">2.7</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">94</td><td style = \"text-align: right;\">6.8</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">5.9</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">95</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">3.3</td><td style = \"text-align: right;\">5.7</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">96</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">5.2</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">97</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">98</td><td style = \"text-align: right;\">6.5</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">5.2</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">99</td><td style = \"text-align: right;\">6.2</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">100</td><td style = \"text-align: right;\">5.9</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 5.1 & 3.5 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 4.9 & 3.0 & 1.4 & 0.2 & setosa \\\\\n",
       "\t3 & 4.7 & 3.2 & 1.3 & 0.2 & setosa \\\\\n",
       "\t4 & 4.6 & 3.1 & 1.5 & 0.2 & setosa \\\\\n",
       "\t5 & 5.0 & 3.6 & 1.4 & 0.2 & setosa \\\\\n",
       "\t6 & 5.4 & 3.9 & 1.7 & 0.4 & setosa \\\\\n",
       "\t7 & 4.6 & 3.4 & 1.4 & 0.3 & setosa \\\\\n",
       "\t8 & 5.0 & 3.4 & 1.5 & 0.2 & setosa \\\\\n",
       "\t9 & 4.4 & 2.9 & 1.4 & 0.2 & setosa \\\\\n",
       "\t10 & 4.9 & 3.1 & 1.5 & 0.1 & setosa \\\\\n",
       "\t11 & 5.4 & 3.7 & 1.5 & 0.2 & setosa \\\\\n",
       "\t12 & 4.8 & 3.4 & 1.6 & 0.2 & setosa \\\\\n",
       "\t13 & 4.8 & 3.0 & 1.4 & 0.1 & setosa \\\\\n",
       "\t14 & 4.3 & 3.0 & 1.1 & 0.1 & setosa \\\\\n",
       "\t15 & 5.8 & 4.0 & 1.2 & 0.2 & setosa \\\\\n",
       "\t16 & 5.7 & 4.4 & 1.5 & 0.4 & setosa \\\\\n",
       "\t17 & 5.4 & 3.9 & 1.3 & 0.4 & setosa \\\\\n",
       "\t18 & 5.1 & 3.5 & 1.4 & 0.3 & setosa \\\\\n",
       "\t19 & 5.7 & 3.8 & 1.7 & 0.3 & setosa \\\\\n",
       "\t20 & 5.1 & 3.8 & 1.5 & 0.3 & setosa \\\\\n",
       "\t21 & 5.4 & 3.4 & 1.7 & 0.2 & setosa \\\\\n",
       "\t22 & 5.1 & 3.7 & 1.5 & 0.4 & setosa \\\\\n",
       "\t23 & 4.6 & 3.6 & 1.0 & 0.2 & setosa \\\\\n",
       "\t24 & 5.1 & 3.3 & 1.7 & 0.5 & setosa \\\\\n",
       "\t$\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m100×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species   \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15  \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────\n",
       "   1 │          5.1          3.5           1.4          0.2  setosa\n",
       "   2 │          4.9          3.0           1.4          0.2  setosa\n",
       "   3 │          4.7          3.2           1.3          0.2  setosa\n",
       "   4 │          4.6          3.1           1.5          0.2  setosa\n",
       "   5 │          5.0          3.6           1.4          0.2  setosa\n",
       "   6 │          5.4          3.9           1.7          0.4  setosa\n",
       "   7 │          4.6          3.4           1.4          0.3  setosa\n",
       "   8 │          5.0          3.4           1.5          0.2  setosa\n",
       "  ⋮  │      ⋮             ⋮            ⋮             ⋮           ⋮\n",
       "  94 │          6.8          3.2           5.9          2.3  virginica\n",
       "  95 │          6.7          3.3           5.7          2.5  virginica\n",
       "  96 │          6.7          3.0           5.2          2.3  virginica\n",
       "  97 │          6.3          2.5           5.0          1.9  virginica\n",
       "  98 │          6.5          3.0           5.2          2.0  virginica\n",
       "  99 │          6.2          3.4           5.4          2.3  virginica\n",
       " 100 │          5.9          3.0           5.1          1.8  virginica\n",
       "\u001b[36m                                                        85 rows omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# in\n",
    "iris[in.(iris.species, Ref([\"virginica\", \"setosa\"])), :]"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### columns"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 50,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>150×2 DataFrame</span></div><div style = \"float: right;\"><span style = \"font-style: italic;\">125 rows omitted</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.4</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.3</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.1</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">11</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">12</td><td style = \"text-align: right;\">1.6</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">13</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.1</td></tr><tr><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">139</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">1.8</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">140</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">2.1</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">141</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.4</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">142</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">2.3</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">143</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.9</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">144</td><td style = \"text-align: right;\">5.9</td><td style = \"text-align: right;\">2.3</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">145</td><td style = \"text-align: right;\">5.7</td><td style = \"text-align: right;\">2.5</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">146</td><td style = \"text-align: right;\">5.2</td><td style = \"text-align: right;\">2.3</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">147</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">1.9</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">148</td><td style = \"text-align: right;\">5.2</td><td style = \"text-align: right;\">2.0</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">149</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">2.3</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">150</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.8</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& petal\\_length & petal\\_width\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & 1.4 & 0.2 \\\\\n",
       "\t2 & 1.4 & 0.2 \\\\\n",
       "\t3 & 1.3 & 0.2 \\\\\n",
       "\t4 & 1.5 & 0.2 \\\\\n",
       "\t5 & 1.4 & 0.2 \\\\\n",
       "\t6 & 1.7 & 0.4 \\\\\n",
       "\t7 & 1.4 & 0.3 \\\\\n",
       "\t8 & 1.5 & 0.2 \\\\\n",
       "\t9 & 1.4 & 0.2 \\\\\n",
       "\t10 & 1.5 & 0.1 \\\\\n",
       "\t11 & 1.5 & 0.2 \\\\\n",
       "\t12 & 1.6 & 0.2 \\\\\n",
       "\t13 & 1.4 & 0.1 \\\\\n",
       "\t14 & 1.1 & 0.1 \\\\\n",
       "\t15 & 1.2 & 0.2 \\\\\n",
       "\t16 & 1.5 & 0.4 \\\\\n",
       "\t17 & 1.3 & 0.4 \\\\\n",
       "\t18 & 1.4 & 0.3 \\\\\n",
       "\t19 & 1.7 & 0.3 \\\\\n",
       "\t20 & 1.5 & 0.3 \\\\\n",
       "\t21 & 1.7 & 0.2 \\\\\n",
       "\t22 & 1.5 & 0.4 \\\\\n",
       "\t23 & 1.0 & 0.2 \\\\\n",
       "\t24 & 1.7 & 0.5 \\\\\n",
       "\t$\\dots$ & $\\dots$ & $\\dots$ \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m150×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\n",
       "─────┼───────────────────────────\n",
       "   1 │          1.4          0.2\n",
       "   2 │          1.4          0.2\n",
       "   3 │          1.3          0.2\n",
       "   4 │          1.5          0.2\n",
       "   5 │          1.4          0.2\n",
       "   6 │          1.7          0.4\n",
       "   7 │          1.4          0.3\n",
       "   8 │          1.5          0.2\n",
       "  ⋮  │      ⋮             ⋮\n",
       " 144 │          5.9          2.3\n",
       " 145 │          5.7          2.5\n",
       " 146 │          5.2          2.3\n",
       " 147 │          5.0          1.9\n",
       " 148 │          5.2          2.0\n",
       " 149 │          5.4          2.3\n",
       " 150 │          5.1          1.8\n",
       "\u001b[36m                 135 rows omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# index (! indicates that underlying columns are not copied)\n",
    "iris[!, 3:4]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 51,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×4 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccc}\n",
       "\t& sepal\\_length & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 5.1 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 4.9 & 1.4 & 0.2 & setosa \\\\\n",
       "\t3 & 4.7 & 1.3 & 0.2 & setosa \\\\\n",
       "\t4 & 4.6 & 1.5 & 0.2 & setosa \\\\\n",
       "\t5 & 5.0 & 1.4 & 0.2 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×4 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼───────────────────────────────────────────────────\n",
       "   1 │          5.1           1.4          0.2  setosa\n",
       "   2 │          4.9           1.4          0.2  setosa\n",
       "   3 │          4.7           1.3          0.2  setosa\n",
       "   4 │          4.6           1.5          0.2  setosa\n",
       "   5 │          5.0           1.4          0.2  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# column names\n",
    "iris[1:5, Cols(:sepal_length, :petal_length, :petal_width, :species)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 52,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 1.4 & 0.2 & setosa \\\\\n",
       "\t3 & 1.3 & 0.2 & setosa \\\\\n",
       "\t4 & 1.5 & 0.2 & setosa \\\\\n",
       "\t5 & 1.4 & 0.2 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼─────────────────────────────────────\n",
       "   1 │          1.4          0.2  setosa\n",
       "   2 │          1.4          0.2  setosa\n",
       "   3 │          1.3          0.2  setosa\n",
       "   4 │          1.5          0.2  setosa\n",
       "   5 │          1.4          0.2  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# column ranges\n",
    "iris[1:5, Between(:petal_length, :species)]\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 53,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×4 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccc}\n",
       "\t& sepal\\_length & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 5.1 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 4.9 & 1.4 & 0.2 & setosa \\\\\n",
       "\t3 & 4.7 & 1.3 & 0.2 & setosa \\\\\n",
       "\t4 & 4.6 & 1.5 & 0.2 & setosa \\\\\n",
       "\t5 & 5.0 & 1.4 & 0.2 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×4 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼───────────────────────────────────────────────────\n",
       "   1 │          5.1           1.4          0.2  setosa\n",
       "   2 │          4.9           1.4          0.2  setosa\n",
       "   3 │          4.7           1.3          0.2  setosa\n",
       "   4 │          4.6           1.5          0.2  setosa\n",
       "   5 │          5.0           1.4          0.2  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# column name and column range\n",
    "iris[1:5, Cols(:sepal_length, Between(:petal_length, :species))]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 54,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>150×3 DataFrame</span></div><div style = \"float: right;\"><span style = \"font-style: italic;\">125 rows omitted</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">11</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">12</td><td style = \"text-align: right;\">1.6</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">13</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">139</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">140</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">141</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.4</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">142</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">143</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">144</td><td style = \"text-align: right;\">5.9</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">145</td><td style = \"text-align: right;\">5.7</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">146</td><td style = \"text-align: right;\">5.2</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">147</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">148</td><td style = \"text-align: right;\">5.2</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">149</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">150</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 1.4 & 0.2 & setosa \\\\\n",
       "\t3 & 1.3 & 0.2 & setosa \\\\\n",
       "\t4 & 1.5 & 0.2 & setosa \\\\\n",
       "\t5 & 1.4 & 0.2 & setosa \\\\\n",
       "\t6 & 1.7 & 0.4 & setosa \\\\\n",
       "\t7 & 1.4 & 0.3 & setosa \\\\\n",
       "\t8 & 1.5 & 0.2 & setosa \\\\\n",
       "\t9 & 1.4 & 0.2 & setosa \\\\\n",
       "\t10 & 1.5 & 0.1 & setosa \\\\\n",
       "\t11 & 1.5 & 0.2 & setosa \\\\\n",
       "\t12 & 1.6 & 0.2 & setosa \\\\\n",
       "\t13 & 1.4 & 0.1 & setosa \\\\\n",
       "\t14 & 1.1 & 0.1 & setosa \\\\\n",
       "\t15 & 1.2 & 0.2 & setosa \\\\\n",
       "\t16 & 1.5 & 0.4 & setosa \\\\\n",
       "\t17 & 1.3 & 0.4 & setosa \\\\\n",
       "\t18 & 1.4 & 0.3 & setosa \\\\\n",
       "\t19 & 1.7 & 0.3 & setosa \\\\\n",
       "\t20 & 1.5 & 0.3 & setosa \\\\\n",
       "\t21 & 1.7 & 0.2 & setosa \\\\\n",
       "\t22 & 1.5 & 0.4 & setosa \\\\\n",
       "\t23 & 1.0 & 0.2 & setosa \\\\\n",
       "\t24 & 1.7 & 0.5 & setosa \\\\\n",
       "\t$\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m150×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species   \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15  \u001b[0m\n",
       "─────┼──────────────────────────────────────\n",
       "   1 │          1.4          0.2  setosa\n",
       "   2 │          1.4          0.2  setosa\n",
       "   3 │          1.3          0.2  setosa\n",
       "   4 │          1.5          0.2  setosa\n",
       "   5 │          1.4          0.2  setosa\n",
       "   6 │          1.7          0.4  setosa\n",
       "   7 │          1.4          0.3  setosa\n",
       "   8 │          1.5          0.2  setosa\n",
       "  ⋮  │      ⋮             ⋮           ⋮\n",
       " 144 │          5.9          2.3  virginica\n",
       " 145 │          5.7          2.5  virginica\n",
       " 146 │          5.2          2.3  virginica\n",
       " 147 │          5.0          1.9  virginica\n",
       " 148 │          5.2          2.0  virginica\n",
       " 149 │          5.4          2.3  virginica\n",
       " 150 │          5.1          1.8  virginica\n",
       "\u001b[36m                            135 rows omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# exclude columns\n",
    "iris[!, Not([:sepal_length, :sepal_width])]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 55,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×2 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_width</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">3.5</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">3.6</td><td style = \"text-align: right;\">0.2</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& sepal\\_width & petal\\_width\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & 3.5 & 0.2 \\\\\n",
       "\t2 & 3.0 & 0.2 \\\\\n",
       "\t3 & 3.2 & 0.2 \\\\\n",
       "\t4 & 3.1 & 0.2 \\\\\n",
       "\t5 & 3.6 & 0.2 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_width \u001b[0m\u001b[1m petal_width \u001b[0m\n",
       "     │\u001b[90m Float64     \u001b[0m\u001b[90m Float64     \u001b[0m\n",
       "─────┼──────────────────────────\n",
       "   1 │         3.5          0.2\n",
       "   2 │         3.0          0.2\n",
       "   3 │         3.2          0.2\n",
       "   4 │         3.1          0.2\n",
       "   5 │         3.6          0.2"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# regex\n",
    "iris[1:5, r\"width\"]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 56,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×2 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& petal\\_length & petal\\_width\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & 1.4 & 0.2 \\\\\n",
       "\t2 & 1.4 & 0.2 \\\\\n",
       "\t3 & 1.3 & 0.2 \\\\\n",
       "\t4 & 1.5 & 0.2 \\\\\n",
       "\t5 & 1.4 & 0.2 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\n",
       "─────┼───────────────────────────\n",
       "   1 │          1.4          0.2\n",
       "   2 │          1.4          0.2\n",
       "   3 │          1.3          0.2\n",
       "   4 │          1.5          0.2\n",
       "   5 │          1.4          0.2"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# regex\n",
    "iris[1:5, r\"petal\"]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 57,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">3.5</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.6</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& sepal\\_length & sepal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 5.1 & 3.5 & setosa \\\\\n",
       "\t2 & 4.9 & 3.0 & setosa \\\\\n",
       "\t3 & 4.7 & 3.2 & setosa \\\\\n",
       "\t4 & 4.6 & 3.1 & setosa \\\\\n",
       "\t5 & 5.0 & 3.6 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼─────────────────────────────────────\n",
       "   1 │          5.1          3.5  setosa\n",
       "   2 │          4.9          3.0  setosa\n",
       "   3 │          4.7          3.2  setosa\n",
       "   4 │          4.6          3.1  setosa\n",
       "   5 │          5.0          3.6  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# regex\n",
    "iris[1:5, r\"s\"]"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Manipulate dataframe"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### rename columns"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 58,
   "metadata": {},
   "outputs": [],
   "source": [
    "# copy iris\n",
    "iris_copy = deepcopy(iris);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 59,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5-element Vector{Symbol}:\n",
       " :sepal_length\n",
       " :sepal_width\n",
       " :petal_length\n",
       " :petal_width\n",
       " :species"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# property names\n",
    "propertynames(iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 60,
   "metadata": {},
   "outputs": [],
   "source": [
    "# rename\n",
    "rename!(iris, :species => :Species)\n",
    "rename!(iris, :sepal_length => :SepalLength, :sepal_width => :SepalWith);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 61,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5-element Vector{Symbol}:\n",
       " :SepalLength\n",
       " :SepalWith\n",
       " :petal_length\n",
       " :petal_width\n",
       " :Species"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# property names\n",
    "propertynames(iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 62,
   "metadata": {},
   "outputs": [],
   "source": [
    "# restore iris\n",
    "iris = deepcopy(iris_copy);"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### reorder columns"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 63,
   "metadata": {},
   "outputs": [],
   "source": [
    "# copy iris\n",
    "iris_copy = deepcopy(iris);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 64,
   "metadata": {},
   "outputs": [],
   "source": [
    "# reorder\n",
    "select!(iris, :species, :petal_length, :sepal_length, :petal_width, :sepal_width);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 65,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>3×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">species</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">sepal_width</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"String15\" style = \"text-align: left;\">String15</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">setosa</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: right;\">3.5</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">setosa</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: right;\">3.0</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">setosa</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">4.7</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: right;\">3.2</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& species & petal\\_length & sepal\\_length & petal\\_width & sepal\\_width\\\\\n",
       "\t\\hline\n",
       "\t& String15 & Float64 & Float64 & Float64 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & setosa & 1.4 & 5.1 & 0.2 & 3.5 \\\\\n",
       "\t2 & setosa & 1.4 & 4.9 & 0.2 & 3.0 \\\\\n",
       "\t3 & setosa & 1.3 & 4.7 & 0.2 & 3.2 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m3×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m species  \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m sepal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m sepal_width \u001b[0m\n",
       "     │\u001b[90m String15 \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64     \u001b[0m\n",
       "─────┼────────────────────────────────────────────────────────────────\n",
       "   1 │ setosa             1.4           5.1          0.2          3.5\n",
       "   2 │ setosa             1.4           4.9          0.2          3.0\n",
       "   3 │ setosa             1.3           4.7          0.2          3.2"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# first rows\n",
    "first(iris, 3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 66,
   "metadata": {},
   "outputs": [],
   "source": [
    "# restore iris\n",
    "iris = deepcopy(iris_copy);"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Missing values"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `allowmissing`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 67,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Missings"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# allowmissing\n",
    "@which allowmissing"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 68,
   "metadata": {},
   "outputs": [],
   "source": [
    "# allowmissing\n",
    "allowmissing!(iris, [:sepal_length, :sepal_width, :petal_length, :petal_width]);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 69,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5-element Vector{Type}:\n",
       " Union{Missing, Float64}\n",
       " Union{Missing, Float64}\n",
       " Union{Missing, Float64}\n",
       " Union{Missing, Float64}\n",
       " String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# element types\n",
    "eltype.(eachcol(iris))"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Create missing values"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 70,
   "metadata": {},
   "outputs": [],
   "source": [
    "# set seed\n",
    "Random.seed!(20_000);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 71,
   "metadata": {},
   "outputs": [],
   "source": [
    "# create missings\n",
    "n = 100\n",
    "for i in 1:n\n",
    "    iris[rand(1:nrow(iris)), rand(1:4)] = missing\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 72,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Type\" style = \"text-align: left;\">Type</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: right;\">24</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: right;\">30</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: right;\">29</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: right;\">17</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& variable & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Int64 & Type\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 24 & Union\\{Missing, Float64\\} \\\\\n",
       "\t2 & sepal\\_width & 30 & Union\\{Missing, Float64\\} \\\\\n",
       "\t3 & petal\\_length & 29 & Union\\{Missing, Float64\\} \\\\\n",
       "\t4 & petal\\_width & 17 & Union\\{Missing, Float64\\} \\\\\n",
       "\t5 & species & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype                  \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m Type                    \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────\n",
       "   1 │ sepal_length        24  Union{Missing, Float64}\n",
       "   2 │ sepal_width         30  Union{Missing, Float64}\n",
       "   3 │ petal_length        29  Union{Missing, Float64}\n",
       "   4 │ petal_width         17  Union{Missing, Float64}\n",
       "   5 │ species              0  String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# count missings\n",
    "describe(iris, :nmissing, :eltype)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 73,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "true"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# check total number of missings\n",
    "sum(describe(iris, :nmissing).nmissing) == n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 74,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">3.5</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.7</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: right;\">1.3</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.6</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">5.0</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64? & Float64? & Float64? & Float64? & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 5.1 & 3.5 & \\emph{missing} & \\emph{missing} & setosa \\\\\n",
       "\t2 & 4.9 & 3.0 & 1.4 & 0.2 & setosa \\\\\n",
       "\t3 & 4.7 & \\emph{missing} & 1.3 & 0.2 & setosa \\\\\n",
       "\t4 & 4.6 & \\emph{missing} & 1.5 & 0.2 & setosa \\\\\n",
       "\t5 & 5.0 & \\emph{missing} & 1.4 & 0.2 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64?     \u001b[0m\u001b[90m Float64?    \u001b[0m\u001b[90m Float64?     \u001b[0m\u001b[90m Float64?    \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼────────────────────────────────────────────────────────────────\n",
       "   1 │          5.1          3.5 \u001b[90m    missing   \u001b[0m\u001b[90m   missing   \u001b[0m setosa\n",
       "   2 │          4.9          3.0           1.4          0.2  setosa\n",
       "   3 │          4.7 \u001b[90m   missing   \u001b[0m          1.3          0.2  setosa\n",
       "   4 │          4.6 \u001b[90m   missing   \u001b[0m          1.5          0.2  setosa\n",
       "   5 │          5.0 \u001b[90m   missing   \u001b[0m          1.4          0.2  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# first rows\n",
    "first(iris, 5)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `completecases`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 75,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "150-element BitVector:\n",
       " 0\n",
       " 1\n",
       " 0\n",
       " 0\n",
       " 0\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 0\n",
       " 1\n",
       " ⋮\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 1\n",
       " 0\n",
       " 0\n",
       " 0\n",
       " 0\n",
       " 0"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "completecases(iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 76,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>71×5 DataFrame</span></div><div style = \"float: right;\"><span style = \"font-style: italic;\">46 rows omitted</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">3.9</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.1</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">3.7</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.6</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">3.3</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.5</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">11</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">12</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.6</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">13</td><td style = \"text-align: right;\">5.5</td><td style = \"text-align: right;\">4.2</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">60</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">61</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.7</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">62</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">3.3</td><td style = \"text-align: right;\">5.7</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">63</td><td style = \"text-align: right;\">6.2</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">64</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">65</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.2</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">66</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">67</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.4</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">68</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">69</td><td style = \"text-align: right;\">5.8</td><td style = \"text-align: right;\">2.7</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">70</td><td style = \"text-align: right;\">6.8</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">5.9</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">71</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">3.3</td><td style = \"text-align: right;\">5.7</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64? & Float64? & Float64? & Float64? & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 4.9 & 3.0 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 5.4 & 3.9 & 1.7 & 0.4 & setosa \\\\\n",
       "\t3 & 4.6 & 3.4 & 1.4 & 0.3 & setosa \\\\\n",
       "\t4 & 5.0 & 3.4 & 1.5 & 0.2 & setosa \\\\\n",
       "\t5 & 4.9 & 3.1 & 1.5 & 0.1 & setosa \\\\\n",
       "\t6 & 4.3 & 3.0 & 1.1 & 0.1 & setosa \\\\\n",
       "\t7 & 5.4 & 3.4 & 1.7 & 0.2 & setosa \\\\\n",
       "\t8 & 5.1 & 3.7 & 1.5 & 0.4 & setosa \\\\\n",
       "\t9 & 4.6 & 3.6 & 1.0 & 0.2 & setosa \\\\\n",
       "\t10 & 5.1 & 3.3 & 1.7 & 0.5 & setosa \\\\\n",
       "\t11 & 4.8 & 3.4 & 1.9 & 0.2 & setosa \\\\\n",
       "\t12 & 5.0 & 3.0 & 1.6 & 0.2 & setosa \\\\\n",
       "\t13 & 5.5 & 4.2 & 1.4 & 0.2 & setosa \\\\\n",
       "\t14 & 4.9 & 3.1 & 1.5 & 0.2 & setosa \\\\\n",
       "\t15 & 5.0 & 3.2 & 1.2 & 0.2 & setosa \\\\\n",
       "\t16 & 5.5 & 3.5 & 1.3 & 0.2 & setosa \\\\\n",
       "\t17 & 4.4 & 3.0 & 1.3 & 0.2 & setosa \\\\\n",
       "\t18 & 4.5 & 2.3 & 1.3 & 0.3 & setosa \\\\\n",
       "\t19 & 4.8 & 3.0 & 1.4 & 0.3 & setosa \\\\\n",
       "\t20 & 5.0 & 3.3 & 1.4 & 0.2 & setosa \\\\\n",
       "\t21 & 7.0 & 3.2 & 4.7 & 1.4 & versicolor \\\\\n",
       "\t22 & 5.7 & 2.8 & 4.5 & 1.3 & versicolor \\\\\n",
       "\t23 & 6.3 & 3.3 & 4.7 & 1.6 & versicolor \\\\\n",
       "\t24 & 4.9 & 2.4 & 3.3 & 1.0 & versicolor \\\\\n",
       "\t$\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m71×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species   \u001b[0m\n",
       "     │\u001b[90m Float64?     \u001b[0m\u001b[90m Float64?    \u001b[0m\u001b[90m Float64?     \u001b[0m\u001b[90m Float64?    \u001b[0m\u001b[90m String15  \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────\n",
       "   1 │          4.9          3.0           1.4          0.2  setosa\n",
       "   2 │          5.4          3.9           1.7          0.4  setosa\n",
       "   3 │          4.6          3.4           1.4          0.3  setosa\n",
       "   4 │          5.0          3.4           1.5          0.2  setosa\n",
       "   5 │          4.9          3.1           1.5          0.1  setosa\n",
       "   6 │          4.3          3.0           1.1          0.1  setosa\n",
       "   7 │          5.4          3.4           1.7          0.2  setosa\n",
       "   8 │          5.1          3.7           1.5          0.4  setosa\n",
       "  ⋮  │      ⋮             ⋮            ⋮             ⋮           ⋮\n",
       "  65 │          6.4          2.8           5.6          2.2  virginica\n",
       "  66 │          6.3          2.8           5.1          1.5  virginica\n",
       "  67 │          6.7          3.1           5.6          2.4  virginica\n",
       "  68 │          6.9          3.1           5.1          2.3  virginica\n",
       "  69 │          5.8          2.7           5.1          1.9  virginica\n",
       "  70 │          6.8          3.2           5.9          2.3  virginica\n",
       "  71 │          6.7          3.3           5.7          2.5  virginica\n",
       "\u001b[36m                                                        56 rows omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "iris[completecases(iris), :]"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `eltype`, `nonmissingtype`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 77,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Union{Missing, Float64}"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "eltype(iris.sepal_length)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 78,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Float64"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "nonmissingtype(eltype(iris.sepal_length))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 79,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5-element Vector{DataType}:\n",
       " Float64\n",
       " Float64\n",
       " Float64\n",
       " Float64\n",
       " String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "nonmissingtype.(eltype.(eachcol(iris)))"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### count missings"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 80,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5-element Vector{Int64}:\n",
       " 24\n",
       " 30\n",
       " 29\n",
       " 17\n",
       "  0"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# vector\n",
    "[sum(ismissing.(col)) for col in eachcol(iris)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 81,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Dict{String, Int64} with 5 entries:\n",
       "  \"sepal_length\" => 24\n",
       "  \"petal_width\"  => 17\n",
       "  \"petal_length\" => 29\n",
       "  \"sepal_width\"  => 30\n",
       "  \"species\"      => 0"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# dictionary\n",
    "Dict(zip(names(iris), [sum(ismissing.(col)) for col in eachcol(iris)]))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 82,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×2 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">nmissing</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: right;\">24</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: right;\">30</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: right;\">29</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: right;\">17</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"text-align: right;\">0</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& variable & nmissing\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Int64\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 24 \\\\\n",
       "\t2 & sepal\\_width & 30 \\\\\n",
       "\t3 & petal\\_length & 29 \\\\\n",
       "\t4 & petal\\_width & 17 \\\\\n",
       "\t5 & species & 0 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m nmissing \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Int64    \u001b[0m\n",
       "─────┼────────────────────────\n",
       "   1 │ sepal_length        24\n",
       "   2 │ sepal_width         30\n",
       "   3 │ petal_length        29\n",
       "   4 │ petal_width         17\n",
       "   5 │ species              0"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# dataframe\n",
    "describe(iris, :nmissing)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `dropmissing`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 83,
   "metadata": {},
   "outputs": [],
   "source": [
    "# copy iris\n",
    "iris_copy = deepcopy(iris);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 84,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>71×5 DataFrame</span></div><div style = \"float: right;\"><span style = \"font-style: italic;\">46 rows omitted</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">3.9</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">4.3</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.1</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">3.7</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.6</td><td style = \"text-align: right;\">1.0</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">3.3</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.5</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">11</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">12</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.6</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">13</td><td style = \"text-align: right;\">5.5</td><td style = \"text-align: right;\">4.2</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td><td style = \"text-align: right;\">&vellip;</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">60</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">2.0</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">61</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.7</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">62</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">3.3</td><td style = \"text-align: right;\">5.7</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">63</td><td style = \"text-align: right;\">6.2</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">4.8</td><td style = \"text-align: right;\">1.8</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">64</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.1</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">65</td><td style = \"text-align: right;\">6.4</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.2</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">66</td><td style = \"text-align: right;\">6.3</td><td style = \"text-align: right;\">2.8</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">67</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">5.6</td><td style = \"text-align: right;\">2.4</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">68</td><td style = \"text-align: right;\">6.9</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">69</td><td style = \"text-align: right;\">5.8</td><td style = \"text-align: right;\">2.7</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">1.9</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">70</td><td style = \"text-align: right;\">6.8</td><td style = \"text-align: right;\">3.2</td><td style = \"text-align: right;\">5.9</td><td style = \"text-align: right;\">2.3</td><td style = \"text-align: left;\">virginica</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">71</td><td style = \"text-align: right;\">6.7</td><td style = \"text-align: right;\">3.3</td><td style = \"text-align: right;\">5.7</td><td style = \"text-align: right;\">2.5</td><td style = \"text-align: left;\">virginica</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64 & Float64 & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 4.9 & 3.0 & 1.4 & 0.2 & setosa \\\\\n",
       "\t2 & 5.4 & 3.9 & 1.7 & 0.4 & setosa \\\\\n",
       "\t3 & 4.6 & 3.4 & 1.4 & 0.3 & setosa \\\\\n",
       "\t4 & 5.0 & 3.4 & 1.5 & 0.2 & setosa \\\\\n",
       "\t5 & 4.9 & 3.1 & 1.5 & 0.1 & setosa \\\\\n",
       "\t6 & 4.3 & 3.0 & 1.1 & 0.1 & setosa \\\\\n",
       "\t7 & 5.4 & 3.4 & 1.7 & 0.2 & setosa \\\\\n",
       "\t8 & 5.1 & 3.7 & 1.5 & 0.4 & setosa \\\\\n",
       "\t9 & 4.6 & 3.6 & 1.0 & 0.2 & setosa \\\\\n",
       "\t10 & 5.1 & 3.3 & 1.7 & 0.5 & setosa \\\\\n",
       "\t11 & 4.8 & 3.4 & 1.9 & 0.2 & setosa \\\\\n",
       "\t12 & 5.0 & 3.0 & 1.6 & 0.2 & setosa \\\\\n",
       "\t13 & 5.5 & 4.2 & 1.4 & 0.2 & setosa \\\\\n",
       "\t14 & 4.9 & 3.1 & 1.5 & 0.2 & setosa \\\\\n",
       "\t15 & 5.0 & 3.2 & 1.2 & 0.2 & setosa \\\\\n",
       "\t16 & 5.5 & 3.5 & 1.3 & 0.2 & setosa \\\\\n",
       "\t17 & 4.4 & 3.0 & 1.3 & 0.2 & setosa \\\\\n",
       "\t18 & 4.5 & 2.3 & 1.3 & 0.3 & setosa \\\\\n",
       "\t19 & 4.8 & 3.0 & 1.4 & 0.3 & setosa \\\\\n",
       "\t20 & 5.0 & 3.3 & 1.4 & 0.2 & setosa \\\\\n",
       "\t21 & 7.0 & 3.2 & 4.7 & 1.4 & versicolor \\\\\n",
       "\t22 & 5.7 & 2.8 & 4.5 & 1.3 & versicolor \\\\\n",
       "\t23 & 6.3 & 3.3 & 4.7 & 1.6 & versicolor \\\\\n",
       "\t24 & 4.9 & 2.4 & 3.3 & 1.0 & versicolor \\\\\n",
       "\t$\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ & $\\dots$ \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m71×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species   \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m String15  \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────────────────────\n",
       "   1 │          4.9          3.0           1.4          0.2  setosa\n",
       "   2 │          5.4          3.9           1.7          0.4  setosa\n",
       "   3 │          4.6          3.4           1.4          0.3  setosa\n",
       "   4 │          5.0          3.4           1.5          0.2  setosa\n",
       "   5 │          4.9          3.1           1.5          0.1  setosa\n",
       "   6 │          4.3          3.0           1.1          0.1  setosa\n",
       "   7 │          5.4          3.4           1.7          0.2  setosa\n",
       "   8 │          5.1          3.7           1.5          0.4  setosa\n",
       "  ⋮  │      ⋮             ⋮            ⋮             ⋮           ⋮\n",
       "  65 │          6.4          2.8           5.6          2.2  virginica\n",
       "  66 │          6.3          2.8           5.1          1.5  virginica\n",
       "  67 │          6.7          3.1           5.6          2.4  virginica\n",
       "  68 │          6.9          3.1           5.1          2.3  virginica\n",
       "  69 │          5.8          2.7           5.1          1.9  virginica\n",
       "  70 │          6.8          3.2           5.9          2.3  virginica\n",
       "  71 │          6.7          3.3           5.7          2.5  virginica\n",
       "\u001b[36m                                                        56 rows omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# dropmissing\n",
    "dropmissing(iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 85,
   "metadata": {},
   "outputs": [],
   "source": [
    "# dropmissing\n",
    "dropmissing!(iris, [:sepal_length, :sepal_width]);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 86,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>7×5 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">sepal_length</th><th style = \"text-align: left;\">sepal_width</th><th style = \"text-align: left;\">petal_length</th><th style = \"text-align: left;\">petal_width</th><th style = \"text-align: left;\">species</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"String15\" style = \"text-align: left;\">String15</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">5.1</td><td style = \"text-align: right;\">3.5</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.0</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">5.4</td><td style = \"text-align: right;\">3.9</td><td style = \"text-align: right;\">1.7</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4.6</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.4</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">5.0</td><td style = \"text-align: right;\">3.4</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">4.4</td><td style = \"text-align: right;\">2.9</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: left;\">setosa</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">4.9</td><td style = \"text-align: right;\">3.1</td><td style = \"text-align: right;\">1.5</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: left;\">setosa</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccc}\n",
       "\t& sepal\\_length & sepal\\_width & petal\\_length & petal\\_width & species\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64? & Float64? & String15\\\\\n",
       "\t\\hline\n",
       "\t1 & 5.1 & 3.5 & \\emph{missing} & \\emph{missing} & setosa \\\\\n",
       "\t2 & 4.9 & 3.0 & 1.4 & 0.2 & setosa \\\\\n",
       "\t3 & 5.4 & 3.9 & 1.7 & 0.4 & setosa \\\\\n",
       "\t4 & 4.6 & 3.4 & 1.4 & 0.3 & setosa \\\\\n",
       "\t5 & 5.0 & 3.4 & 1.5 & 0.2 & setosa \\\\\n",
       "\t6 & 4.4 & 2.9 & \\emph{missing} & 0.2 & setosa \\\\\n",
       "\t7 & 4.9 & 3.1 & 1.5 & 0.1 & setosa \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m7×5 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m sepal_length \u001b[0m\u001b[1m sepal_width \u001b[0m\u001b[1m petal_length \u001b[0m\u001b[1m petal_width \u001b[0m\u001b[1m species  \u001b[0m\n",
       "     │\u001b[90m Float64      \u001b[0m\u001b[90m Float64     \u001b[0m\u001b[90m Float64?     \u001b[0m\u001b[90m Float64?    \u001b[0m\u001b[90m String15 \u001b[0m\n",
       "─────┼────────────────────────────────────────────────────────────────\n",
       "   1 │          5.1          3.5 \u001b[90m    missing   \u001b[0m\u001b[90m   missing   \u001b[0m setosa\n",
       "   2 │          4.9          3.0           1.4          0.2  setosa\n",
       "   3 │          5.4          3.9           1.7          0.4  setosa\n",
       "   4 │          4.6          3.4           1.4          0.3  setosa\n",
       "   5 │          5.0          3.4           1.5          0.2  setosa\n",
       "   6 │          4.4          2.9 \u001b[90m    missing   \u001b[0m         0.2  setosa\n",
       "   7 │          4.9          3.1           1.5          0.1  setosa"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# first rows\n",
    "first(iris, 7)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `replace`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 87,
   "metadata": {},
   "outputs": [],
   "source": [
    "# restore copy\n",
    "iris = deepcopy(iris_copy);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 88,
   "metadata": {},
   "outputs": [],
   "source": [
    "# replace values (without changing element type)\n",
    "replace!(iris.sepal_width, missing => 1_000);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 89,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Type\" style = \"text-align: left;\">Type</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: right;\">24</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: right;\">29</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: right;\">17</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& variable & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Int64 & Type\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 24 & Union\\{Missing, Float64\\} \\\\\n",
       "\t2 & sepal\\_width & 0 & Union\\{Missing, Float64\\} \\\\\n",
       "\t3 & petal\\_length & 29 & Union\\{Missing, Float64\\} \\\\\n",
       "\t4 & petal\\_width & 17 & Union\\{Missing, Float64\\} \\\\\n",
       "\t5 & species & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype                  \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m Type                    \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────\n",
       "   1 │ sepal_length        24  Union{Missing, Float64}\n",
       "   2 │ sepal_width          0  Union{Missing, Float64}\n",
       "   3 │ petal_length        29  Union{Missing, Float64}\n",
       "   4 │ petal_width         17  Union{Missing, Float64}\n",
       "   5 │ species              0  String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# describe\n",
    "describe(iris, :nmissing, :eltype)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### `coalesce`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 90,
   "metadata": {},
   "outputs": [],
   "source": [
    "# restore copy\n",
    "iris = deepcopy(iris_copy);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 91,
   "metadata": {},
   "outputs": [],
   "source": [
    "# replace missing values (with changing the element type)\n",
    "iris.sepal_width = coalesce.(iris.sepal_width, 1_000);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 92,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Type\" style = \"text-align: left;\">Type</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: right;\">24</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Real</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: right;\">29</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: right;\">17</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& variable & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Int64 & Type\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 24 & Union\\{Missing, Float64\\} \\\\\n",
       "\t2 & sepal\\_width & 0 & Real \\\\\n",
       "\t3 & petal\\_length & 29 & Union\\{Missing, Float64\\} \\\\\n",
       "\t4 & petal\\_width & 17 & Union\\{Missing, Float64\\} \\\\\n",
       "\t5 & species & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype                  \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m Type                    \u001b[0m\n",
       "─────┼─────────────────────────────────────────────────\n",
       "   1 │ sepal_length        24  Union{Missing, Float64}\n",
       "   2 │ sepal_width          0  Real\n",
       "   3 │ petal_length        29  Union{Missing, Float64}\n",
       "   4 │ petal_width         17  Union{Missing, Float64}\n",
       "   5 │ species              0  String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# describe\n",
    "describe(iris, :nmissing, :eltype)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Replace values by `mean` per `species`"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 93,
   "metadata": {},
   "outputs": [],
   "source": [
    "# restore copy\n",
    "iris = deepcopy(iris_copy);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 94,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Type\" style = \"text-align: left;\">Type</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: left;\">5.81032</td><td style = \"text-align: left;\">4.3</td><td style = \"text-align: left;\">5.7</td><td style = \"text-align: left;\">7.9</td><td style = \"text-align: right;\">24</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: left;\">3.01833</td><td style = \"text-align: left;\">2.0</td><td style = \"text-align: left;\">3.0</td><td style = \"text-align: left;\">4.4</td><td style = \"text-align: right;\">30</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: left;\">3.71901</td><td style = \"text-align: left;\">1.0</td><td style = \"text-align: left;\">4.3</td><td style = \"text-align: left;\">6.7</td><td style = \"text-align: right;\">29</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: left;\">1.20977</td><td style = \"text-align: left;\">0.1</td><td style = \"text-align: left;\">1.3</td><td style = \"text-align: left;\">2.5</td><td style = \"text-align: right;\">17</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">setosa</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Union… & Any & Union… & Any & Int64 & Type\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 5.81032 & 4.3 & 5.7 & 7.9 & 24 & Union\\{Missing, Float64\\} \\\\\n",
       "\t2 & sepal\\_width & 3.01833 & 2.0 & 3.0 & 4.4 & 30 & Union\\{Missing, Float64\\} \\\\\n",
       "\t3 & petal\\_length & 3.71901 & 1.0 & 4.3 & 6.7 & 29 & Union\\{Missing, Float64\\} \\\\\n",
       "\t4 & petal\\_width & 1.20977 & 0.1 & 1.3 & 2.5 & 17 & Union\\{Missing, Float64\\} \\\\\n",
       "\t5 & species &  & setosa &  & virginica & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min    \u001b[0m\u001b[1m median \u001b[0m\u001b[1m max       \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype     \u001b[0m ⋯\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Union…  \u001b[0m\u001b[90m Any    \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Any       \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m Type       \u001b[0m ⋯\n",
       "─────┼──────────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length  5.81032  4.3     5.7     7.9              24  Union{Missi ⋯\n",
       "   2 │ sepal_width   3.01833  2.0     3.0     4.4              30  Union{Missi\n",
       "   3 │ petal_length  3.71901  1.0     4.3     6.7              29  Union{Missi\n",
       "   4 │ petal_width   1.20977  0.1     1.3     2.5              17  Union{Missi\n",
       "   5 │ species      \u001b[90m         \u001b[0m setosa \u001b[90m        \u001b[0m virginica         0  String15    ⋯\n",
       "\u001b[36m                                                                1 column omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# describe\n",
    "describe(iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 95,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Statistics"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# mean from statistics.jl package\n",
    "@which mean"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 96,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "3.7190082644628117"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# mean for petal_length (independent of species)\n",
    "mean(skipmissing(iris.petal_length))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 97,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "4.269047619047619"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# mean petal_length for species versicolor\n",
    "mean(skipmissing(iris[isequal.(iris.species, \"versicolor\"), :petal_length]))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 98,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>3×2 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">species</th><th style = \"text-align: left;\">mean</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"String15\" style = \"text-align: left;\">String15</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">setosa</td><td style = \"text-align: right;\">1.46829</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">versicolor</td><td style = \"text-align: right;\">4.26905</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">5.53947</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& species & mean\\\\\n",
       "\t\\hline\n",
       "\t& String15 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & setosa & 1.46829 \\\\\n",
       "\t2 & versicolor & 4.26905 \\\\\n",
       "\t3 & virginica & 5.53947 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m3×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m species    \u001b[0m\u001b[1m mean    \u001b[0m\n",
       "     │\u001b[90m String15   \u001b[0m\u001b[90m Float64 \u001b[0m\n",
       "─────┼─────────────────────\n",
       "   1 │ setosa      1.46829\n",
       "   2 │ versicolor  4.26905\n",
       "   3 │ virginica   5.53947"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# mean petal_length per species\n",
    "means_before = combine(groupby(iris, :species), :petal_length .=> mean∘skipmissing .=> :mean)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 99,
   "metadata": {},
   "outputs": [],
   "source": [
    "# replace missing petal_length values by the mean per species\n",
    "for group in groupby(iris, :species)\n",
    "    group[ismissing.(group.petal_length), :petal_length] .= mean(skipmissing(group.petal_length))\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 100,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Type\" style = \"text-align: left;\">Type</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: left;\">5.81032</td><td style = \"text-align: left;\">4.3</td><td style = \"text-align: left;\">5.7</td><td style = \"text-align: left;\">7.9</td><td style = \"text-align: right;\">24</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: left;\">3.01833</td><td style = \"text-align: left;\">2.0</td><td style = \"text-align: left;\">3.0</td><td style = \"text-align: left;\">4.4</td><td style = \"text-align: right;\">30</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: left;\">3.75894</td><td style = \"text-align: left;\">1.0</td><td style = \"text-align: left;\">4.26905</td><td style = \"text-align: left;\">6.7</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: left;\">1.20977</td><td style = \"text-align: left;\">0.1</td><td style = \"text-align: left;\">1.3</td><td style = \"text-align: left;\">2.5</td><td style = \"text-align: right;\">17</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">setosa</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Union… & Any & Union… & Any & Int64 & Type\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 5.81032 & 4.3 & 5.7 & 7.9 & 24 & Union\\{Missing, Float64\\} \\\\\n",
       "\t2 & sepal\\_width & 3.01833 & 2.0 & 3.0 & 4.4 & 30 & Union\\{Missing, Float64\\} \\\\\n",
       "\t3 & petal\\_length & 3.75894 & 1.0 & 4.26905 & 6.7 & 0 & Union\\{Missing, Float64\\} \\\\\n",
       "\t4 & petal\\_width & 1.20977 & 0.1 & 1.3 & 2.5 & 17 & Union\\{Missing, Float64\\} \\\\\n",
       "\t5 & species &  & setosa &  & virginica & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min    \u001b[0m\u001b[1m median  \u001b[0m\u001b[1m max       \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype    \u001b[0m ⋯\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Union…  \u001b[0m\u001b[90m Any    \u001b[0m\u001b[90m Union…  \u001b[0m\u001b[90m Any       \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m Type      \u001b[0m ⋯\n",
       "─────┼──────────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length  5.81032  4.3     5.7      7.9              24  Union{Miss ⋯\n",
       "   2 │ sepal_width   3.01833  2.0     3.0      4.4              30  Union{Miss\n",
       "   3 │ petal_length  3.75894  1.0     4.26905  6.7               0  Union{Miss\n",
       "   4 │ petal_width   1.20977  0.1     1.3      2.5              17  Union{Miss\n",
       "   5 │ species      \u001b[90m         \u001b[0m setosa \u001b[90m         \u001b[0m virginica         0  String15   ⋯\n",
       "\u001b[36m                                                                1 column omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# describe\n",
    "describe(iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 101,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>3×2 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">species</th><th style = \"text-align: left;\">mean</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"String15\" style = \"text-align: left;\">String15</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">setosa</td><td style = \"text-align: right;\">1.46829</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">versicolor</td><td style = \"text-align: right;\">4.26905</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">5.53947</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& species & mean\\\\\n",
       "\t\\hline\n",
       "\t& String15 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & setosa & 1.46829 \\\\\n",
       "\t2 & versicolor & 4.26905 \\\\\n",
       "\t3 & virginica & 5.53947 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m3×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m species    \u001b[0m\u001b[1m mean    \u001b[0m\n",
       "     │\u001b[90m String15   \u001b[0m\u001b[90m Float64 \u001b[0m\n",
       "─────┼─────────────────────\n",
       "   1 │ setosa      1.46829\n",
       "   2 │ versicolor  4.26905\n",
       "   3 │ virginica   5.53947"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# mean petal_length per species\n",
    "means_after = combine(groupby(iris, :species), :petal_length .=> mean .=> :mean)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 102,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "true"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# compare means before and after replacing values\n",
    "isapprox(means_before.mean, means_after.mean)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 103,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "true"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# same comparison, different notation\n",
    "means_before.mean ≈ means_after.mean"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 104,
   "metadata": {},
   "outputs": [],
   "source": [
    "# disallow missing values\n",
    "disallowmissing!(iris, :petal_length);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 105,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Type\" style = \"text-align: left;\">Type</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: left;\">5.81032</td><td style = \"text-align: left;\">4.3</td><td style = \"text-align: left;\">5.7</td><td style = \"text-align: left;\">7.9</td><td style = \"text-align: right;\">24</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: left;\">3.01833</td><td style = \"text-align: left;\">2.0</td><td style = \"text-align: left;\">3.0</td><td style = \"text-align: left;\">4.4</td><td style = \"text-align: right;\">30</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: left;\">3.75894</td><td style = \"text-align: left;\">1.0</td><td style = \"text-align: left;\">4.26905</td><td style = \"text-align: left;\">6.7</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: left;\">1.20977</td><td style = \"text-align: left;\">0.1</td><td style = \"text-align: left;\">1.3</td><td style = \"text-align: left;\">2.5</td><td style = \"text-align: right;\">17</td><td style = \"text-align: left;\">Union{Missing, Float64}</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">setosa</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Union… & Any & Union… & Any & Int64 & Type\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 5.81032 & 4.3 & 5.7 & 7.9 & 24 & Union\\{Missing, Float64\\} \\\\\n",
       "\t2 & sepal\\_width & 3.01833 & 2.0 & 3.0 & 4.4 & 30 & Union\\{Missing, Float64\\} \\\\\n",
       "\t3 & petal\\_length & 3.75894 & 1.0 & 4.26905 & 6.7 & 0 & Float64 \\\\\n",
       "\t4 & petal\\_width & 1.20977 & 0.1 & 1.3 & 2.5 & 17 & Union\\{Missing, Float64\\} \\\\\n",
       "\t5 & species &  & setosa &  & virginica & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min    \u001b[0m\u001b[1m median  \u001b[0m\u001b[1m max       \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype    \u001b[0m ⋯\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Union…  \u001b[0m\u001b[90m Any    \u001b[0m\u001b[90m Union…  \u001b[0m\u001b[90m Any       \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m Type      \u001b[0m ⋯\n",
       "─────┼──────────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length  5.81032  4.3     5.7      7.9              24  Union{Miss ⋯\n",
       "   2 │ sepal_width   3.01833  2.0     3.0      4.4              30  Union{Miss\n",
       "   3 │ petal_length  3.75894  1.0     4.26905  6.7               0  Float64\n",
       "   4 │ petal_width   1.20977  0.1     1.3      2.5              17  Union{Miss\n",
       "   5 │ species      \u001b[90m         \u001b[0m setosa \u001b[90m         \u001b[0m virginica         0  String15   ⋯\n",
       "\u001b[36m                                                                1 column omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# describe\n",
    "describe(iris)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 106,
   "metadata": {},
   "outputs": [],
   "source": [
    "# replace missing values by the mean per species for all numeric columns\n",
    "for grp in groupby(iris, :species)\n",
    "    for col in names(iris, Union{Missing, Float64})\n",
    "        grp[ismissing.(grp[!, col]), col] .= mean(skipmissing(grp[!, col]))\n",
    "    end\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 107,
   "metadata": {},
   "outputs": [],
   "source": [
    "# disallow missing values\n",
    "disallowmissing!(iris);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 108,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×7 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">variable</th><th style = \"text-align: left;\">mean</th><th style = \"text-align: left;\">min</th><th style = \"text-align: left;\">median</th><th style = \"text-align: left;\">max</th><th style = \"text-align: left;\">nmissing</th><th style = \"text-align: left;\">eltype</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Symbol\" style = \"text-align: left;\">Symbol</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Union{Nothing, Float64}\" style = \"text-align: left;\">Union…</th><th title = \"Any\" style = \"text-align: left;\">Any</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"DataType\" style = \"text-align: left;\">DataType</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: left;\">sepal_length</td><td style = \"text-align: left;\">5.82851</td><td style = \"text-align: left;\">4.3</td><td style = \"text-align: left;\">5.8</td><td style = \"text-align: left;\">7.9</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: left;\">sepal_width</td><td style = \"text-align: left;\">3.03569</td><td style = \"text-align: left;\">2.0</td><td style = \"text-align: left;\">3.0</td><td style = \"text-align: left;\">4.4</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: left;\">petal_length</td><td style = \"text-align: left;\">3.75894</td><td style = \"text-align: left;\">1.0</td><td style = \"text-align: left;\">4.26905</td><td style = \"text-align: left;\">6.7</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: left;\">petal_width</td><td style = \"text-align: left;\">1.20098</td><td style = \"text-align: left;\">0.1</td><td style = \"text-align: left;\">1.3</td><td style = \"text-align: left;\">2.5</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">Float64</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: left;\">species</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">setosa</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: left;\">virginica</td><td style = \"text-align: right;\">0</td><td style = \"text-align: left;\">String15</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccccccc}\n",
       "\t& variable & mean & min & median & max & nmissing & eltype\\\\\n",
       "\t\\hline\n",
       "\t& Symbol & Union… & Any & Union… & Any & Int64 & DataType\\\\\n",
       "\t\\hline\n",
       "\t1 & sepal\\_length & 5.82851 & 4.3 & 5.8 & 7.9 & 0 & Float64 \\\\\n",
       "\t2 & sepal\\_width & 3.03569 & 2.0 & 3.0 & 4.4 & 0 & Float64 \\\\\n",
       "\t3 & petal\\_length & 3.75894 & 1.0 & 4.26905 & 6.7 & 0 & Float64 \\\\\n",
       "\t4 & petal\\_width & 1.20098 & 0.1 & 1.3 & 2.5 & 0 & Float64 \\\\\n",
       "\t5 & species &  & setosa &  & virginica & 0 & String15 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×7 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m variable     \u001b[0m\u001b[1m mean    \u001b[0m\u001b[1m min    \u001b[0m\u001b[1m median  \u001b[0m\u001b[1m max       \u001b[0m\u001b[1m nmissing \u001b[0m\u001b[1m eltype   \u001b[0m\n",
       "     │\u001b[90m Symbol       \u001b[0m\u001b[90m Union…  \u001b[0m\u001b[90m Any    \u001b[0m\u001b[90m Union…  \u001b[0m\u001b[90m Any       \u001b[0m\u001b[90m Int64    \u001b[0m\u001b[90m DataType \u001b[0m\n",
       "─────┼───────────────────────────────────────────────────────────────────────\n",
       "   1 │ sepal_length  5.82851  4.3     5.8      7.9               0  Float64\n",
       "   2 │ sepal_width   3.03569  2.0     3.0      4.4               0  Float64\n",
       "   3 │ petal_length  3.75894  1.0     4.26905  6.7               0  Float64\n",
       "   4 │ petal_width   1.20098  0.1     1.3      2.5               0  Float64\n",
       "   5 │ species      \u001b[90m         \u001b[0m setosa \u001b[90m         \u001b[0m virginica         0  String15"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# describe\n",
    "describe(iris)"
   ]
  },
  {
   "attachments": {},
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Create dataframe"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 109,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>3×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th><th style = \"text-align: left;\">z</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">4</td><td style = \"text-align: right;\">9</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">5</td><td style = \"text-align: right;\">9</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">6</td><td style = \"text-align: right;\">9</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& x & y & z\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Int64 & Int64\\\\\n",
       "\t\\hline\n",
       "\t1 & 10 & 4 & 9 \\\\\n",
       "\t2 & 20 & 5 & 9 \\\\\n",
       "\t3 & 30 & 6 & 9 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m3×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x     \u001b[0m\u001b[1m y     \u001b[0m\u001b[1m z     \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\n",
       "─────┼─────────────────────\n",
       "   1 │    10      4      9\n",
       "   2 │    20      5      9\n",
       "   3 │    30      6      9"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Create dataframe with column data from vector, range, or constant\n",
    "DataFrame(x = [10, 20, 30], y = 4:6, z = 9)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 110,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>2×2 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">1</td><td style = \"text-align: right;\">2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">3</td><td style = \"text-align: right;\">4</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& x & y\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Int64\\\\\n",
       "\t\\hline\n",
       "\t1 & 1 & 2 \\\\\n",
       "\t2 & 3 & 4 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m2×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x     \u001b[0m\u001b[1m y     \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\n",
       "─────┼──────────────\n",
       "   1 │     1      2\n",
       "   2 │     3      4"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Create dataframe from a vector of named tuples\n",
    "DataFrame([(x=1, y=2), (x=3, y=4)])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 111,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>2×2 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">30</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">40</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& x & y\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Int64\\\\\n",
       "\t\\hline\n",
       "\t1 & 10 & 30 \\\\\n",
       "\t2 & 20 & 40 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m2×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x     \u001b[0m\u001b[1m y     \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\n",
       "─────┼──────────────\n",
       "   1 │    10     30\n",
       "   2 │    20     40"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Create dataframe from pairs of column name and data\n",
    "DataFrame(\"x\" => [10, 20], \"y\" => [30 ,40])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 112,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x1</th><th style = \"text-align: left;\">x2</th><th style = \"text-align: left;\">x3</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">0.179999</td><td style = \"text-align: right;\">0.551681</td><td style = \"text-align: right;\">0.465886</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">0.802308</td><td style = \"text-align: right;\">0.291485</td><td style = \"text-align: right;\">0.140368</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">0.674031</td><td style = \"text-align: right;\">0.758827</td><td style = \"text-align: right;\">0.762979</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">0.21323</td><td style = \"text-align: right;\">0.381562</td><td style = \"text-align: right;\">0.269365</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">0.846688</td><td style = \"text-align: right;\">0.961208</td><td style = \"text-align: right;\">0.405862</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& x1 & x2 & x3\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & 0.179999 & 0.551681 & 0.465886 \\\\\n",
       "\t2 & 0.802308 & 0.291485 & 0.140368 \\\\\n",
       "\t3 & 0.674031 & 0.758827 & 0.762979 \\\\\n",
       "\t4 & 0.21323 & 0.381562 & 0.269365 \\\\\n",
       "\t5 & 0.846688 & 0.961208 & 0.405862 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x1       \u001b[0m\u001b[1m x2       \u001b[0m\u001b[1m x3       \u001b[0m\n",
       "     │\u001b[90m Float64  \u001b[0m\u001b[90m Float64  \u001b[0m\u001b[90m Float64  \u001b[0m\n",
       "─────┼──────────────────────────────\n",
       "   1 │ 0.179999  0.551681  0.465886\n",
       "   2 │ 0.802308  0.291485  0.140368\n",
       "   3 │ 0.674031  0.758827  0.762979\n",
       "   4 │ 0.21323   0.381562  0.269365\n",
       "   5 │ 0.846688  0.961208  0.405862"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Create data frame from a matrix\n",
    "DataFrame(rand(5, 3), :auto)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 113,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th><th style = \"text-align: left;\">z</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">0.288159</td><td style = \"text-align: right;\">0.989546</td><td style = \"text-align: right;\">0.165529</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">0.958112</td><td style = \"text-align: right;\">0.0759519</td><td style = \"text-align: right;\">0.487494</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">0.953123</td><td style = \"text-align: right;\">0.808883</td><td style = \"text-align: right;\">0.618207</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">0.536712</td><td style = \"text-align: right;\">0.839786</td><td style = \"text-align: right;\">0.446132</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">0.876099</td><td style = \"text-align: right;\">0.228024</td><td style = \"text-align: right;\">0.310324</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& x & y & z\\\\\n",
       "\t\\hline\n",
       "\t& Float64 & Float64 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & 0.288159 & 0.989546 & 0.165529 \\\\\n",
       "\t2 & 0.958112 & 0.0759519 & 0.487494 \\\\\n",
       "\t3 & 0.953123 & 0.808883 & 0.618207 \\\\\n",
       "\t4 & 0.536712 & 0.839786 & 0.446132 \\\\\n",
       "\t5 & 0.876099 & 0.228024 & 0.310324 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x        \u001b[0m\u001b[1m y         \u001b[0m\u001b[1m z        \u001b[0m\n",
       "     │\u001b[90m Float64  \u001b[0m\u001b[90m Float64   \u001b[0m\u001b[90m Float64  \u001b[0m\n",
       "─────┼───────────────────────────────\n",
       "   1 │ 0.288159  0.989546   0.165529\n",
       "   2 │ 0.958112  0.0759519  0.487494\n",
       "   3 │ 0.953123  0.808883   0.618207\n",
       "   4 │ 0.536712  0.839786   0.446132\n",
       "   5 │ 0.876099  0.228024   0.310324"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Create dataframe from a matrix\n",
    "DataFrame(rand(5, 3), [:x, :y, :z])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 114,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>0×0 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|}\n",
       "\t& \\\\\n",
       "\t\\hline\n",
       "\t& \\\\\n",
       "\t\\hline\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m0×0 DataFrame\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Create an empty dataframe without column\n",
    "DataFrame()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 115,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>0×2 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& x & y\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Float64\\\\\n",
       "\t\\hline\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m0×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x     \u001b[0m\u001b[1m y       \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Float64 \u001b[0m\n",
       "─────┴────────────────"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Create an empty data frame with typed columns\n",
    "df = DataFrame(x = Int[], y = Float64[])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 116,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>4×2 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">0.1</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">0.2</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">0.3</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">0.4</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cc}\n",
       "\t& x & y\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Float64\\\\\n",
       "\t\\hline\n",
       "\t1 & 10 & 0.1 \\\\\n",
       "\t2 & 20 & 0.2 \\\\\n",
       "\t3 & 30 & 0.3 \\\\\n",
       "\t4 & 40 & 0.4 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m4×2 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x     \u001b[0m\u001b[1m y       \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Float64 \u001b[0m\n",
       "─────┼────────────────\n",
       "   1 │    10      0.1\n",
       "   2 │    20      0.2\n",
       "   3 │    30      0.3\n",
       "   4 │    40      0.4"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Append data\n",
    "append!(df, DataFrame(x = Int[10, 20], y = Float64[.1, .2]))\n",
    "append!(df, DataFrame(x = Int[30, 40], y = Float64[.3, .4]))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 117,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>4×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th><th style = \"text-align: left;\">newcol</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">5</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: right;\">10</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: right;\">15</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: right;\">20</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& x & y & newcol\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Float64 & Int64\\\\\n",
       "\t\\hline\n",
       "\t1 & 10 & 0.1 & 5 \\\\\n",
       "\t2 & 20 & 0.2 & 10 \\\\\n",
       "\t3 & 30 & 0.3 & 15 \\\\\n",
       "\t4 & 40 & 0.4 & 20 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m4×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x     \u001b[0m\u001b[1m y       \u001b[0m\u001b[1m newcol \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Int64  \u001b[0m\n",
       "─────┼────────────────────────\n",
       "   1 │    10      0.1       5\n",
       "   2 │    20      0.2      10\n",
       "   3 │    30      0.3      15\n",
       "   4 │    40      0.4      20"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Insert column\n",
    "insertcols!(df, 3, \"newcol\" => 5:5:20)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 118,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th><th style = \"text-align: left;\">newcol</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">5</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: right;\">10</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: right;\">15</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: right;\">20</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">50</td><td style = \"text-align: right;\">0.5</td><td style = \"text-align: right;\">25</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& x & y & newcol\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Float64 & Int64\\\\\n",
       "\t\\hline\n",
       "\t1 & 10 & 0.1 & 5 \\\\\n",
       "\t2 & 20 & 0.2 & 10 \\\\\n",
       "\t3 & 30 & 0.3 & 15 \\\\\n",
       "\t4 & 40 & 0.4 & 20 \\\\\n",
       "\t5 & 50 & 0.5 & 25 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x     \u001b[0m\u001b[1m y       \u001b[0m\u001b[1m newcol \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Int64  \u001b[0m\n",
       "─────┼────────────────────────\n",
       "   1 │    10      0.1       5\n",
       "   2 │    20      0.2      10\n",
       "   3 │    30      0.3      15\n",
       "   4 │    40      0.4      20\n",
       "   5 │    50      0.5      25"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Push single row\n",
    "push!(df, [50, .5, 25])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 119,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Aloow missing\n",
    "allowmissing!(df);"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 120,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>6×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th><th style = \"text-align: left;\">newcol</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Union{Missing, Int64}\" style = \"text-align: left;\">Int64?</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"Union{Missing, Int64}\" style = \"text-align: left;\">Int64?</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">5</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: right;\">10</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: right;\">15</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: right;\">20</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">50</td><td style = \"text-align: right;\">0.5</td><td style = \"text-align: right;\">25</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& x & y & newcol\\\\\n",
       "\t\\hline\n",
       "\t& Int64? & Float64? & Int64?\\\\\n",
       "\t\\hline\n",
       "\t1 & 10 & 0.1 & 5 \\\\\n",
       "\t2 & 20 & 0.2 & 10 \\\\\n",
       "\t3 & 30 & 0.3 & 15 \\\\\n",
       "\t4 & 40 & 0.4 & 20 \\\\\n",
       "\t5 & 50 & 0.5 & 25 \\\\\n",
       "\t6 & \\emph{missing} & \\emph{missing} & \\emph{missing} \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m6×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x       \u001b[0m\u001b[1m y         \u001b[0m\u001b[1m newcol  \u001b[0m\n",
       "     │\u001b[90m Int64?  \u001b[0m\u001b[90m Float64?  \u001b[0m\u001b[90m Int64?  \u001b[0m\n",
       "─────┼─────────────────────────────\n",
       "   1 │      10        0.1        5\n",
       "   2 │      20        0.2       10\n",
       "   3 │      30        0.3       15\n",
       "   4 │      40        0.4       20\n",
       "   5 │      50        0.5       25\n",
       "   6 │\u001b[90m missing \u001b[0m\u001b[90m missing   \u001b[0m\u001b[90m missing \u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Push single row\n",
    "push!(df, [missing, missing, missing])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 121,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>6×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th><th style = \"text-align: left;\">newcol</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Union{Missing, Int64}\" style = \"text-align: left;\">Int64?</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"Union{Missing, Int64}\" style = \"text-align: left;\">Int64?</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">5</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: right;\">10</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: right;\">15</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: right;\">20</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">50</td><td style = \"text-align: right;\">0.5</td><td style = \"text-align: right;\">25</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">99</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& x & y & newcol\\\\\n",
       "\t\\hline\n",
       "\t& Int64? & Float64? & Int64?\\\\\n",
       "\t\\hline\n",
       "\t1 & 10 & 0.1 & 5 \\\\\n",
       "\t2 & 20 & 0.2 & 10 \\\\\n",
       "\t3 & 30 & 0.3 & 15 \\\\\n",
       "\t4 & 40 & 0.4 & 20 \\\\\n",
       "\t5 & 50 & 0.5 & 25 \\\\\n",
       "\t6 & 99 & \\emph{missing} & \\emph{missing} \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m6×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x      \u001b[0m\u001b[1m y         \u001b[0m\u001b[1m newcol  \u001b[0m\n",
       "     │\u001b[90m Int64? \u001b[0m\u001b[90m Float64?  \u001b[0m\u001b[90m Int64?  \u001b[0m\n",
       "─────┼────────────────────────────\n",
       "   1 │     10        0.1        5\n",
       "   2 │     20        0.2       10\n",
       "   3 │     30        0.3       15\n",
       "   4 │     40        0.4       20\n",
       "   5 │     50        0.5       25\n",
       "   6 │     99 \u001b[90m missing   \u001b[0m\u001b[90m missing \u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Replace missing Values (datatype column unchanged)\n",
    "replace!(df.x, missing=>99);\n",
    "df"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 122,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>6×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">x</th><th style = \"text-align: left;\">y</th><th style = \"text-align: left;\">newcol</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Union{Missing, Int64}\" style = \"text-align: left;\">Int64?</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Union{Missing, Int64}\" style = \"text-align: left;\">Int64?</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">5</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: right;\">10</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: right;\">15</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: right;\">20</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">50</td><td style = \"text-align: right;\">0.5</td><td style = \"text-align: right;\">25</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">99</td><td style = \"text-align: right;\">0.99</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& x & y & newcol\\\\\n",
       "\t\\hline\n",
       "\t& Int64? & Float64 & Int64?\\\\\n",
       "\t\\hline\n",
       "\t1 & 10 & 0.1 & 5 \\\\\n",
       "\t2 & 20 & 0.2 & 10 \\\\\n",
       "\t3 & 30 & 0.3 & 15 \\\\\n",
       "\t4 & 40 & 0.4 & 20 \\\\\n",
       "\t5 & 50 & 0.5 & 25 \\\\\n",
       "\t6 & 99 & 0.99 & \\emph{missing} \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m6×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m x      \u001b[0m\u001b[1m y       \u001b[0m\u001b[1m newcol  \u001b[0m\n",
       "     │\u001b[90m Int64? \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Int64?  \u001b[0m\n",
       "─────┼──────────────────────────\n",
       "   1 │     10     0.1         5\n",
       "   2 │     20     0.2        10\n",
       "   3 │     30     0.3        15\n",
       "   4 │     40     0.4        20\n",
       "   5 │     50     0.5        25\n",
       "   6 │     99     0.99 \u001b[90m missing \u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Replace missing value (with datatype change)\n",
    "df.y = coalesce.(df.y, .99)\n",
    "df"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 123,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>6×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">a</th><th style = \"text-align: left;\">b</th><th style = \"text-align: left;\">c</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Union{Missing, Int64}\" style = \"text-align: left;\">Int64?</th><th title = \"Float64\" style = \"text-align: left;\">Float64</th><th title = \"Union{Missing, Int64}\" style = \"text-align: left;\">Int64?</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">0.1</td><td style = \"text-align: right;\">5</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">0.2</td><td style = \"text-align: right;\">10</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">0.3</td><td style = \"text-align: right;\">15</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">0.4</td><td style = \"text-align: right;\">20</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">50</td><td style = \"text-align: right;\">0.5</td><td style = \"text-align: right;\">25</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">99</td><td style = \"text-align: right;\">0.99</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& a & b & c\\\\\n",
       "\t\\hline\n",
       "\t& Int64? & Float64 & Int64?\\\\\n",
       "\t\\hline\n",
       "\t1 & 10 & 0.1 & 5 \\\\\n",
       "\t2 & 20 & 0.2 & 10 \\\\\n",
       "\t3 & 30 & 0.3 & 15 \\\\\n",
       "\t4 & 40 & 0.4 & 20 \\\\\n",
       "\t5 & 50 & 0.5 & 25 \\\\\n",
       "\t6 & 99 & 0.99 & \\emph{missing} \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m6×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m a      \u001b[0m\u001b[1m b       \u001b[0m\u001b[1m c       \u001b[0m\n",
       "     │\u001b[90m Int64? \u001b[0m\u001b[90m Float64 \u001b[0m\u001b[90m Int64?  \u001b[0m\n",
       "─────┼──────────────────────────\n",
       "   1 │     10     0.1         5\n",
       "   2 │     20     0.2        10\n",
       "   3 │     30     0.3        15\n",
       "   4 │     40     0.4        20\n",
       "   5 │     50     0.5        25\n",
       "   6 │     99     0.99 \u001b[90m missing \u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Rename columns\n",
    "rename!(df, string.('a':'c'))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 124,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>2×3 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">a</th><th style = \"text-align: left;\">b</th><th style = \"text-align: left;\">c</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">50</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">60</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|ccc}\n",
       "\t& a & b & c\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Int64 & Int64\\\\\n",
       "\t\\hline\n",
       "\t1 & 10 & 30 & 50 \\\\\n",
       "\t2 & 20 & 40 & 60 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m2×3 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m a     \u001b[0m\u001b[1m b     \u001b[0m\u001b[1m c     \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\n",
       "─────┼─────────────────────\n",
       "   1 │    10     30     50\n",
       "   2 │    20     40     60"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# Horizontal concat\n",
    "df1 = DataFrame(a=[10, 20])\n",
    "df2 = DataFrame(b=[30, 40], c=[50, 60])\n",
    "hcat(df1, df2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 125,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>10×8 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">A</th><th style = \"text-align: left;\">B</th><th style = \"text-align: left;\">C</th><th style = \"text-align: left;\">D</th><th style = \"text-align: left;\">E</th><th style = \"text-align: left;\">G</th><th style = \"text-align: left;\">F</th><th style = \"text-align: left;\">H</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"String\" style = \"text-align: left;\">String</th><th title = \"Union{Nothing, Char}\" style = \"text-align: left;\">Union…</th><th title = \"Bool\" style = \"text-align: left;\">Bool</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">1</td><td style = \"text-align: right;\">5</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.325977</td><td style = \"text-align: left;\">red</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">true</td><td style = \"text-align: right;\">0.26906</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">2</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">red</td><td style = \"text-align: left;\">A</td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">-4.27396e18</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">3</td><td style = \"text-align: right;\">15</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">green</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">-4.27396e18</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">4</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">blue</td><td style = \"text-align: left;\">A</td><td style = \"text-align: right;\">false</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">5</td><td style = \"text-align: right;\">25</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">blue</td><td style = \"text-align: left;\">A</td><td style = \"text-align: right;\">false</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">6</td><td style = \"text-align: right;\">6</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">green</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">true</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">7</td><td style = \"text-align: right;\">7</td><td style = \"text-align: right;\">35</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">blue</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">0.26906</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">8</td><td style = \"text-align: right;\">8</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">blue</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: right;\">true</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">9</td><td style = \"text-align: right;\">9</td><td style = \"text-align: right;\">45</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">red</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">0.26906</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">10</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">50</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">green</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">true</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccccccc}\n",
       "\t& A & B & C & D & E & G & F & H\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Int64 & Int64 & Float64? & String & Union… & Bool & Float64?\\\\\n",
       "\t\\hline\n",
       "\t1 & 1 & 5 & 100 & 0.325977 & red & B & 1 & 0.26906 \\\\\n",
       "\t2 & 2 & 10 & 100 & \\emph{missing} & red & A & 0 & -4.27396e18 \\\\\n",
       "\t3 & 3 & 15 & 100 & 0.549051 & green & B & 0 & -4.27396e18 \\\\\n",
       "\t4 & 4 & 20 & 100 & 0.549051 & blue & A & 0 & \\emph{missing} \\\\\n",
       "\t5 & 5 & 25 & 100 & \\emph{missing} & blue & A & 0 & \\emph{missing} \\\\\n",
       "\t6 & 6 & 30 & 100 & \\emph{missing} & green & B & 1 & \\emph{missing} \\\\\n",
       "\t7 & 7 & 35 & 100 & 0.549051 & blue &  & 0 & 0.26906 \\\\\n",
       "\t8 & 8 & 40 & 100 & \\emph{missing} & blue &  & 1 & \\emph{missing} \\\\\n",
       "\t9 & 9 & 45 & 100 & 0.549051 & red & B & 0 & 0.26906 \\\\\n",
       "\t10 & 10 & 50 & 100 & \\emph{missing} & green & B & 1 & \\emph{missing} \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m10×8 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m A     \u001b[0m\u001b[1m B     \u001b[0m\u001b[1m C     \u001b[0m\u001b[1m D              \u001b[0m\u001b[1m E      \u001b[0m\u001b[1m G      \u001b[0m\u001b[1m F     \u001b[0m\u001b[1m H          \u001b[0m ⋯\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Float64?       \u001b[0m\u001b[90m String \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Bool  \u001b[0m\u001b[90m Float64?   \u001b[0m ⋯\n",
       "─────┼──────────────────────────────────────────────────────────────────────────\n",
       "   1 │     1      5    100        0.325977  red     B        true        0.269 ⋯\n",
       "   2 │     2     10    100 \u001b[90m missing        \u001b[0m red     A       false       -4.273\n",
       "   3 │     3     15    100        0.549051  green   B       false       -4.273\n",
       "   4 │     4     20    100        0.549051  blue    A       false \u001b[90m missing    \u001b[0m\n",
       "   5 │     5     25    100 \u001b[90m missing        \u001b[0m blue    A       false \u001b[90m missing    \u001b[0m ⋯\n",
       "   6 │     6     30    100 \u001b[90m missing        \u001b[0m green   B        true \u001b[90m missing    \u001b[0m\n",
       "   7 │     7     35    100        0.549051  blue   \u001b[90m        \u001b[0m false        0.269\n",
       "   8 │     8     40    100 \u001b[90m missing        \u001b[0m blue   \u001b[90m        \u001b[0m  true \u001b[90m missing    \u001b[0m\n",
       "   9 │     9     45    100        0.549051  red     B       false        0.269 ⋯\n",
       "  10 │    10     50    100 \u001b[90m missing        \u001b[0m green   B        true \u001b[90m missing    \u001b[0m\n",
       "\u001b[36m                                                                1 column omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# create dataframe\n",
    "\n",
    "Random.seed!(1234); # set seed for reproducibility\n",
    "\n",
    "n = 10 # number of rows\n",
    "\n",
    "df = DataFrame(\n",
    "    A = 1:n, # range\n",
    "    B = [x * 5 for x in 1:n], # array comprehension\n",
    "    C = 100, # broadcasting\n",
    "    D = rand([rand(), rand(), missing], n),\n",
    "    E = rand([\"red\", \"green\", \"blue\"], n),\n",
    "    G = rand(['A', 'B', nothing], n),\n",
    "    F = rand([true, false], n),\n",
    "    H = rand([rand(Int64), rand(), missing], n),\n",
    ")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 126,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>4×8 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">A</th><th style = \"text-align: left;\">B</th><th style = \"text-align: left;\">C</th><th style = \"text-align: left;\">D</th><th style = \"text-align: left;\">E</th><th style = \"text-align: left;\">G</th><th style = \"text-align: left;\">F</th><th style = \"text-align: left;\">H</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"String\" style = \"text-align: left;\">String</th><th title = \"Union{Nothing, Char}\" style = \"text-align: left;\">Union…</th><th title = \"Bool\" style = \"text-align: left;\">Bool</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">1</td><td style = \"text-align: right;\">5</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.325977</td><td style = \"text-align: left;\">red</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">true</td><td style = \"text-align: right;\">0.26906</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">3</td><td style = \"text-align: right;\">15</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">green</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">-4.27396e18</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">7</td><td style = \"text-align: right;\">35</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">blue</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">0.26906</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">9</td><td style = \"text-align: right;\">45</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">red</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">0.26906</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccccccc}\n",
       "\t& A & B & C & D & E & G & F & H\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Int64 & Int64 & Float64? & String & Union… & Bool & Float64?\\\\\n",
       "\t\\hline\n",
       "\t1 & 1 & 5 & 100 & 0.325977 & red & B & 1 & 0.26906 \\\\\n",
       "\t2 & 3 & 15 & 100 & 0.549051 & green & B & 0 & -4.27396e18 \\\\\n",
       "\t3 & 7 & 35 & 100 & 0.549051 & blue &  & 0 & 0.26906 \\\\\n",
       "\t4 & 9 & 45 & 100 & 0.549051 & red & B & 0 & 0.26906 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m4×8 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m A     \u001b[0m\u001b[1m B     \u001b[0m\u001b[1m C     \u001b[0m\u001b[1m D        \u001b[0m\u001b[1m E      \u001b[0m\u001b[1m G      \u001b[0m\u001b[1m F     \u001b[0m\u001b[1m H           \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Float64? \u001b[0m\u001b[90m String \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Bool  \u001b[0m\u001b[90m Float64?    \u001b[0m\n",
       "─────┼───────────────────────────────────────────────────────────────────\n",
       "   1 │     1      5    100  0.325977  red     B        true   0.26906\n",
       "   2 │     3     15    100  0.549051  green   B       false  -4.27396e18\n",
       "   3 │     7     35    100  0.549051  blue   \u001b[90m        \u001b[0m false   0.26906\n",
       "   4 │     9     45    100  0.549051  red     B       false   0.26906"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# complete cases (nothing ≠ missing !!, see row 3, col G)\n",
    "df[completecases(df), :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 127,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "5-element Vector{Int64}:\n",
       "  2\n",
       "  5\n",
       "  6\n",
       "  8\n",
       " 10"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# findall missing\n",
    "findall(ismissing.(df.D))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 128,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×8 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">A</th><th style = \"text-align: left;\">B</th><th style = \"text-align: left;\">C</th><th style = \"text-align: left;\">D</th><th style = \"text-align: left;\">E</th><th style = \"text-align: left;\">G</th><th style = \"text-align: left;\">F</th><th style = \"text-align: left;\">H</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"String\" style = \"text-align: left;\">String</th><th title = \"Union{Nothing, Char}\" style = \"text-align: left;\">Union…</th><th title = \"Bool\" style = \"text-align: left;\">Bool</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">2</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">red</td><td style = \"text-align: left;\">A</td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">-4.27396e18</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">5</td><td style = \"text-align: right;\">25</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">blue</td><td style = \"text-align: left;\">A</td><td style = \"text-align: right;\">false</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">6</td><td style = \"text-align: right;\">30</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">green</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">true</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">8</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">blue</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: right;\">true</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">10</td><td style = \"text-align: right;\">50</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">green</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">true</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccccccc}\n",
       "\t& A & B & C & D & E & G & F & H\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Int64 & Int64 & Float64? & String & Union… & Bool & Float64?\\\\\n",
       "\t\\hline\n",
       "\t1 & 2 & 10 & 100 & \\emph{missing} & red & A & 0 & -4.27396e18 \\\\\n",
       "\t2 & 5 & 25 & 100 & \\emph{missing} & blue & A & 0 & \\emph{missing} \\\\\n",
       "\t3 & 6 & 30 & 100 & \\emph{missing} & green & B & 1 & \\emph{missing} \\\\\n",
       "\t4 & 8 & 40 & 100 & \\emph{missing} & blue &  & 1 & \\emph{missing} \\\\\n",
       "\t5 & 10 & 50 & 100 & \\emph{missing} & green & B & 1 & \\emph{missing} \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×8 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m A     \u001b[0m\u001b[1m B     \u001b[0m\u001b[1m C     \u001b[0m\u001b[1m D        \u001b[0m\u001b[1m E      \u001b[0m\u001b[1m G      \u001b[0m\u001b[1m F     \u001b[0m\u001b[1m H                \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Float64? \u001b[0m\u001b[90m String \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Bool  \u001b[0m\u001b[90m Float64?         \u001b[0m\n",
       "─────┼────────────────────────────────────────────────────────────────────────\n",
       "   1 │     2     10    100 \u001b[90m  missing \u001b[0m red     A       false       -4.27396e18\n",
       "   2 │     5     25    100 \u001b[90m  missing \u001b[0m blue    A       false \u001b[90m missing          \u001b[0m\n",
       "   3 │     6     30    100 \u001b[90m  missing \u001b[0m green   B        true \u001b[90m missing          \u001b[0m\n",
       "   4 │     8     40    100 \u001b[90m  missing \u001b[0m blue   \u001b[90m        \u001b[0m  true \u001b[90m missing          \u001b[0m\n",
       "   5 │    10     50    100 \u001b[90m  missing \u001b[0m green   B        true \u001b[90m missing          \u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# findall missing\n",
    "df[findall(ismissing.(df.D)), :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 129,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "10-element BitVector:\n",
       " 1\n",
       " 0\n",
       " 1\n",
       " 1\n",
       " 0\n",
       " 0\n",
       " 1\n",
       " 0\n",
       " 1\n",
       " 0"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# findall all not missing\n",
    ".!ismissing.(df.D)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 130,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>5×8 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">A</th><th style = \"text-align: left;\">B</th><th style = \"text-align: left;\">C</th><th style = \"text-align: left;\">D</th><th style = \"text-align: left;\">E</th><th style = \"text-align: left;\">G</th><th style = \"text-align: left;\">F</th><th style = \"text-align: left;\">H</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"String\" style = \"text-align: left;\">String</th><th title = \"Union{Nothing, Char}\" style = \"text-align: left;\">Union…</th><th title = \"Bool\" style = \"text-align: left;\">Bool</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">1</td><td style = \"text-align: right;\">5</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.325977</td><td style = \"text-align: left;\">red</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">true</td><td style = \"text-align: right;\">0.26906</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">3</td><td style = \"text-align: right;\">15</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">green</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">-4.27396e18</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">3</td><td style = \"text-align: right;\">4</td><td style = \"text-align: right;\">20</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">blue</td><td style = \"text-align: left;\">A</td><td style = \"text-align: right;\">false</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">4</td><td style = \"text-align: right;\">7</td><td style = \"text-align: right;\">35</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">blue</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">0.26906</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">5</td><td style = \"text-align: right;\">9</td><td style = \"text-align: right;\">45</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">red</td><td style = \"text-align: left;\">B</td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">0.26906</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccccccc}\n",
       "\t& A & B & C & D & E & G & F & H\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Int64 & Int64 & Float64? & String & Union… & Bool & Float64?\\\\\n",
       "\t\\hline\n",
       "\t1 & 1 & 5 & 100 & 0.325977 & red & B & 1 & 0.26906 \\\\\n",
       "\t2 & 3 & 15 & 100 & 0.549051 & green & B & 0 & -4.27396e18 \\\\\n",
       "\t3 & 4 & 20 & 100 & 0.549051 & blue & A & 0 & \\emph{missing} \\\\\n",
       "\t4 & 7 & 35 & 100 & 0.549051 & blue &  & 0 & 0.26906 \\\\\n",
       "\t5 & 9 & 45 & 100 & 0.549051 & red & B & 0 & 0.26906 \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m5×8 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m A     \u001b[0m\u001b[1m B     \u001b[0m\u001b[1m C     \u001b[0m\u001b[1m D        \u001b[0m\u001b[1m E      \u001b[0m\u001b[1m G      \u001b[0m\u001b[1m F     \u001b[0m\u001b[1m H                \u001b[0m\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Float64? \u001b[0m\u001b[90m String \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Bool  \u001b[0m\u001b[90m Float64?         \u001b[0m\n",
       "─────┼────────────────────────────────────────────────────────────────────────\n",
       "   1 │     1      5    100  0.325977  red     B        true        0.26906\n",
       "   2 │     3     15    100  0.549051  green   B       false       -4.27396e18\n",
       "   3 │     4     20    100  0.549051  blue    A       false \u001b[90m missing          \u001b[0m\n",
       "   4 │     7     35    100  0.549051  blue   \u001b[90m        \u001b[0m false        0.26906\n",
       "   5 │     9     45    100  0.549051  red     B       false        0.26906"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# findall not missing\n",
    "df[findall(.!ismissing.(df.D)), :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 131,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "2-element Vector{Int64}:\n",
       " 7\n",
       " 8"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# findall nothing\n",
    "findall(isnothing.(df.G))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 132,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/html": [
       "<div><div style = \"float: left;\"><span>2×8 DataFrame</span></div><div style = \"clear: both;\"></div></div><div class = \"data-frame\" style = \"overflow-x: scroll;\"><table class = \"data-frame\" style = \"margin-bottom: 6px;\"><thead><tr class = \"header\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">Row</th><th style = \"text-align: left;\">A</th><th style = \"text-align: left;\">B</th><th style = \"text-align: left;\">C</th><th style = \"text-align: left;\">D</th><th style = \"text-align: left;\">E</th><th style = \"text-align: left;\">G</th><th style = \"text-align: left;\">F</th><th style = \"text-align: left;\">H</th></tr><tr class = \"subheader headerLastRow\"><th class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\"></th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Int64\" style = \"text-align: left;\">Int64</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th><th title = \"String\" style = \"text-align: left;\">String</th><th title = \"Union{Nothing, Char}\" style = \"text-align: left;\">Union…</th><th title = \"Bool\" style = \"text-align: left;\">Bool</th><th title = \"Union{Missing, Float64}\" style = \"text-align: left;\">Float64?</th></tr></thead><tbody><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">1</td><td style = \"text-align: right;\">7</td><td style = \"text-align: right;\">35</td><td style = \"text-align: right;\">100</td><td style = \"text-align: right;\">0.549051</td><td style = \"text-align: left;\">blue</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: right;\">false</td><td style = \"text-align: right;\">0.26906</td></tr><tr><td class = \"rowNumber\" style = \"font-weight: bold; text-align: right;\">2</td><td style = \"text-align: right;\">8</td><td style = \"text-align: right;\">40</td><td style = \"text-align: right;\">100</td><td style = \"font-style: italic; text-align: right;\">missing</td><td style = \"text-align: left;\">blue</td><td style = \"font-style: italic; text-align: left;\"></td><td style = \"text-align: right;\">true</td><td style = \"font-style: italic; text-align: right;\">missing</td></tr></tbody></table></div>"
      ],
      "text/latex": [
       "\\begin{tabular}{r|cccccccc}\n",
       "\t& A & B & C & D & E & G & F & H\\\\\n",
       "\t\\hline\n",
       "\t& Int64 & Int64 & Int64 & Float64? & String & Union… & Bool & Float64?\\\\\n",
       "\t\\hline\n",
       "\t1 & 7 & 35 & 100 & 0.549051 & blue &  & 0 & 0.26906 \\\\\n",
       "\t2 & 8 & 40 & 100 & \\emph{missing} & blue &  & 1 & \\emph{missing} \\\\\n",
       "\\end{tabular}\n"
      ],
      "text/plain": [
       "\u001b[1m2×8 DataFrame\u001b[0m\n",
       "\u001b[1m Row \u001b[0m│\u001b[1m A     \u001b[0m\u001b[1m B     \u001b[0m\u001b[1m C     \u001b[0m\u001b[1m D              \u001b[0m\u001b[1m E      \u001b[0m\u001b[1m G      \u001b[0m\u001b[1m F     \u001b[0m\u001b[1m H          \u001b[0m ⋯\n",
       "     │\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Int64 \u001b[0m\u001b[90m Float64?       \u001b[0m\u001b[90m String \u001b[0m\u001b[90m Union… \u001b[0m\u001b[90m Bool  \u001b[0m\u001b[90m Float64?   \u001b[0m ⋯\n",
       "─────┼──────────────────────────────────────────────────────────────────────────\n",
       "   1 │     7     35    100        0.549051  blue   \u001b[90m        \u001b[0m false        0.269 ⋯\n",
       "   2 │     8     40    100 \u001b[90m missing        \u001b[0m blue   \u001b[90m        \u001b[0m  true \u001b[90m missing    \u001b[0m\n",
       "\u001b[36m                                                                1 column omitted\u001b[0m"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# findall nothing\n",
    "df[findall(isnothing.(df.G)), :]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 133,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Float64"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# convert datatype\n",
    "replace!(df.D, missing => 1_000);\n",
    "df.D = convert.(Float64, df.D)\n",
    "eltype(df.D)"
   ]
  }
 ],
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  "kernelspec": {
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