polars.DataFrame.plot support tracking

[dangotbanned]

What is your suggestion?

Related polars PR w/ @binste comment

• feat(python!): Use Altair in DataFrame.plot pola-rs/polars#17995

Thought it would make sense to track in an issue here, not only in a polars PR.

If you haven't read though that thread, please check it first as there are many related issues/repos that have been linked.
Including pandas, pd_vega, altair_pandas

Example end-goal

Providing a limited API via a plot accessor, that shortens paths like below:

from datetime import date

from packaging.version import Version
import polars as pl
import altair as alt

df = pl.DataFrame(
        {
            "date": [date(2020, 1, 2), date(2020, 1, 3), date(2020, 1, 4)] * 2,
            "price": [1, 4, 6, 1, 5, 2],
            "stock": ["a", "a", "a", "b", "b", "b"]
        }
    )

if Version(pl.__version__) >= Version("1.5.0"): # Currently 1.4.0
    df.plot.line(x="date", y="price", color="stock")
else:
    alt.Chart(df).mark_line().encode(x="date", y="price", color="stock")

This should provide:

• Access to common marks
• Arguments passed to .encode()
• Some level of typing on those parameters

@MarcoGorelli has already done some great work in the original PR, and the simplest approach would be exposing some types for them to import

As mentioned here and here an alt.Chart is returned - which can be used for further customisation using the full altair API.