Uncomfortable output of mode() in pandas Dataframe

Question

I have a dataframe with several columns (the features).

>>> print(df)

   col1  col2
a     1     1
b     2     2
c     3     3
d     3     2
         


        

Answer 1

Because Series.mode() can return multiple values:

consider the following DF:

In [77]: df
Out[77]:
   col1  col2
a     1     1
b     2     2
c     3     3
d     3     2
e     2     3

In [78]: df['col1'].mode()
Out[78]:
0    2
1    3
dtype: int64

From docstring:

Empty if nothing occurs at least 2 times. Always returns Series even if only one value.

If you want to chose the first value:

In [83]: df['col1'].mode().iloc[0]
Out[83]: 2

In [84]: df['col1'].mode()[0]
Out[84]: 2