Is it possible to filter Pandas DataFrame column if column is a list?

Question

import pandas as pd

dafr = pd.DataFrame({'a': [1,2,3], 'b': [[1,2,3],[2,3,4],[3,4,5]]})

I try to do something like:

dafr[dafr['b'].isin(2)]

which should return rows that has lists: [1,2,3] & [2,3,4].

I wonder if this is possible?

Answer 1

isin returns whether the column value is in what you pass. You want to check if what you pass is in the column value.

As far as I know there is no direct shortcut for this, but you can do it using map :

>>> dafr[dafr.b.map(lambda x: 2 in x)]
    a          b
0  1  [1, 2, 3]
1  2  [2, 3, 4]

Answer 2

dafr[dafr['b'].apply(lambda x: 2 in x)]

Answer 3

如果将b存储为元组列而不是列表列，则afr[dafr['b'].apply(lambda x: 2 in x)]将执行得非常快。