Advanced Functions Test Solutions.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#Advanced Functions Test Solutions\n",
    "\n",
    "### For this test, you should use the built-in functions to be able to write the requested functions in one line."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "###Problem 1\n",
    "\n",
    "Use map to create a function which finds the length of each word in the phrase\n",
    "(broken by spaces) and return the values in a list.\n",
    "\n",
    "The function will have an input of a string, and output a list of integers."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def word_lengths(phrase):\n",
    "    \n",
    "    return list(map(len, phrase.split()))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[3, 4, 3, 3, 5, 2, 4, 6]"
      ]
     },
     "execution_count": 4,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "word_lengths('How long are the words in this phrase')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "###Problem 2 \n",
    "\n",
    "Use reduce to take a list of digits and return the number that they\n",
    "correspond to. *Do not convert the integers to strings!* "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def digits_to_num(digits):\n",
    "    \n",
    "    return reduce(lambda x,y: x*10 + y,digits)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "34321"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "digits_to_num([3,4,3,2,1])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "###Problem 3\n",
    "\n",
    "Use filter to return the words from a list of words which start with a target letter."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def filter_words(word_list, letter):\n",
    "    \n",
    "    return filter(lambda word: word[0]==letter,word_list)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['hello', 'ham', 'hi', 'heart']"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "l = ['hello','are','cat','dog','ham','hi','go','to','heart']\n",
    "filter_words(l,'h')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "###Problem 4\n",
    "\n",
    "Use zip and list comprehension to return a list of the same length where each value is the two strings from\n",
    "L1 and L2 concatenated together with connector between them. Look at the example output below:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def concatenate(L1, L2, connector):\n",
    "    \n",
    "    return [word1+connector+word2 for (word1,word2) in zip(L1,L2)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['A-a', 'B-b']"
      ]
     },
     "execution_count": 14,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "concatenate(['A','B'],['a','b'],'-')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "###Problem 5\n",
    "\n",
    "Use enumerate and other skills to return a dictionary which has the values of the list as keys and the index as the value. You may assume that a value will only appear once in the given list.\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def d_list(L):\n",
    "    \n",
    "    return {key:value for value,key in enumerate(L)}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'a': 0, 'b': 1, 'c': 2}"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "d_list(['a','b','c'])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "###Problem 6\n",
    "\n",
    "Use enumerate and other skills from above to return the count of the number of items in the list whose value equals its index.\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def count_match_index(L):\n",
    "   \n",
    "    return len([num for count,num in enumerate(L) if num == count])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "text/plain": [
       "4"
      ]
     },
     "execution_count": 24,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "count_match_index([0,2,2,1,5,5,6,10])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Great Job!"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 2",
   "language": "python",
   "name": "python2"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 2
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython2",
   "version": "2.7.10"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 0
}