Tabeline

Tabeline is a data frame and data grammar library. You write the expressions in strings and supply them to methods on the DataFrame class. The strings are parsed by Parsita and converted into Polars for execution.

Tabeline draws inspiration from dplyr, the data grammar of R's tidyverse, especially for its methods names. The filter, mutate, group_by, and summarize methods should all feel familiar. But Tabeline is as proper a Python library as can be, using methods instead of pipes, like is standard in R.

Tabeline uses Polars under the hood, but adds a lot of handling of edge cases from Polars, which otherwise result in crashes or behavior that is not type stable.

See the Documentation for the full user guide.

Installation

It is recommended to install Tabeline from PyPI using pip.

pip install tabeline

Motivating example

from tabeline import DataFrame

# Construct a data frame using clean syntax
# from_csv, from_pandas, and from_polars are also available 
df = DataFrame(
    id=[0, 0, 0, 0, 1, 1, 1, 1, 1],
    t=[0, 6, 12, 24, 0, 6, 12, 24, 48],
    y=[0, 2, 3, 1, 0, 4, 3, 2, 1],
)

# Use data grammar methods and string expressions to define
# transformed data frames
analysis = (
    df
    .filter("t <= 24")
    .group_by("id")
    .summarize(auc="trapz(t, y)")
)

print(analysis)
# shape: (2, 2)
# ┌─────┬──────┐
# │ id  ┆ auc  │
# │ --- ┆ ---  │
# │ i64 ┆ f64  │
# ╞═════╪══════╡
# │ 0   ┆ 45.0 │
# ├╌╌╌╌╌┼╌╌╌╌╌╌┤
# │ 1   ┆ 63.0 │
# └─────┴──────┘