[Python] Polars Pandas-like groupby save to files by each value

Boiling down a bigger problem to its essentials, I would like to do this:

import numpy as np
import pandas as pd

df = pd.DataFrame({'a': np.random.randint(0, 5, 1000), 'b': np.random.random(1000)})

for aval, subdf in df.groupby('a'):
subdf.to_parquet(f'/tmp/{aval}.parquet')


in Polars using LazyFrame:

import numpy as np
import pandas as pd
import polars as pl

df = pd.DataFrame({'a': np.random.randint(0, 5, 1000), 'b': np.random.random(1000)})

lf = pl.LazyFrame(df)
# ???


I would like to be able to control the name of the output files in a similar way.

Thanks!

Continue reading...