Returning a DataFrame from Series.apply when the supplied function returns a Series is deprecated

Question

The way I have always split a column containing lists into multiple columns is:

df['column_with_lists'].apply(pd.Series)

This returns a new dataframe that can then be concatenated.

With pandas 2.1, this now raises: FutureWarning: Returning a DataFrame from Series.apply when the supplied function returns a Series is deprecated and will be removed in a future version.

What is now the recommended way to split a column containing lists?

Asked By: mrgou

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Source

Answer 1

Making Series.apply return a DataFrame is deprecated because :

This pattern was very slow and it’s recommended to use alternative methods to archive the same goal. Check GH52116 for more details/context

You can for example do a classical construction like below to turn-off the FutureWarning :

df = pd.DataFrame({"column_with_lists": [range(4, 6), range(1, 5)]})

out = pd.DataFrame(df["column_with_lists"].tolist())

Output :

print(out)

   0  1      2      3
0  4  5    NaN    NaN
1  1  2 3.0000 4.0000

Answered By: Timeless

Returning a DataFrame from Series.apply when the supplied function returns a Series is deprecated

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