python - Pandas: compare list objects in Series

Question

In my dataframe a column is made up of lists, for example:

df = pd.DataFrame({'A':[[1,2],[2,4],[3,1]]})

I need to find out the location of list [1,2] in this dataframe. I tried:

df.loc[df['A'] == [1,2]]

and

df.loc[df['A'] == [[1,2]]]

but failed totally. The comparison seems very simple but that just doesn't work. Am I missing something here?

Answer 1

Do not use list in cell, it creates a lot of problem for pandas. If you do need an object column, using tuple:

df.A.map(tuple).isin([(1,2)])
Out[293]: 
0     True
1    False
2    False
Name: A, dtype: bool
#df[df.A.map(tuple).isin([(1,2)])]