Creating a data frame

The central class of Tabeline is tabeline.DataFrame. There is little to do with Tabeline other than constructing a DataFrame and invoking methods on it to get a different DataFrame.

To create a DataFrame, you can either use the constructor or several static methods on the class.

`DataFrame`

The constructor for DataFrame takes an arbitrary number of named arguments. The name of each argument creates a column with the same name. The value of each named argument must be a list, which becomes the values under that column. Naturally, all provided lists must have the same length.

from tabeline import DataFrame

df = DataFrame(
    name=["A New Hope", "The Empire Strikes Back", "Return of the Jedi"],
    episode=[4, 5, 6],
    release_year=[1977, 1980, 1983],
)

Note

If you poke around in the code, you may notice that the contructor also takes positional arguments. Those are part of the private constructor; don't use them.

`DataFrame.from_dict`

This is basically the same as the constructor, except the arguments are kept as a single dictionary instead of being splatted out. The values of the dictionary can be any Sequence.

from tabeline import DataFrame

data = {
    "name": ["A New Hope", "The Empire Strikes Back", "Return of the Jedi"],
    "episode": [4, 5, 6],
    "release_year": [1977, 1980, 1983],
}

df = DataFrame.from_dict(data)

`DataFrame.read_csv`

Reads a data frame from a CSV file.

from pathlib import Path
from tabeline import DataFrame

df = DataFrame.read_csv(Path("star_wars.csv"))

`DataFrame.from_pandas`

Create a tabeline.DataFrame from a pandas.DataFrame. This ignores the index. Use df.reset_index() on the Pandas DataFrame to copy the index to columns first. This requires that the pandas extra is installed (i.e. pip install tabeline[pandas]) because this conversion through Polars relies on PyArrow, which may not otherwise be installed.

import pandas as pd
from tabeline import DataFrame

pandas_df = pd.DataFrame(dict(
    name=["A New Hope", "The Empire Strikes Back", "Return of the Jedi"],
    episode=[4, 5, 6],
    release_year=[1977, 1980, 1983],
))

df = DataFrame.from_pandas(pandas_df)

`DataFrame.from_polars`

Create a tabeline.DataFrame from a polars.DataFrame. Because Tabeline uses Polars internally, this is a simple wrapper.

import polars as pl
from tabeline import DataFrame

polars_df = pl.DataFrame(dict(
    name=["A New Hope", "The Empire Strikes Back", "Return of the Jedi"],
    episode=[4, 5, 6],
    release_year=[1977, 1980, 1983],
))

df = DataFrame.from_polars(polars_df)