Check if value in dataframe exists in another column for each row

Question

Dataframe in question, df:

colA colB
1  [1, 4, 5]
4  [3, nan, nan]

I'm trying to return a Series which has True where colA's value is in colB's value for each row.

The result should be:

True
False

I tried: df.colA.isin(df.colB) - but that doesn't do the trick because colB's values are in lists

Great that works, thanks! First one is good because it's memory efficient — Hanuman95
– Hanuman95, Commented Sep 30, 2020 at 22:00

BENY · Accepted Answer · 2020-09-30 22:12:31Z

1

You need to unpack the list columns before isin

m = pd.DataFrame(df['colB'].tolist(),index=df.index).isin(df['colA']).any(axis=1)

answered Sep 30, 2020 at 22:12

BENY

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