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

I would like to compute the mode of one of them. This is what happens:

>>> print(df['col1'].mode())

0    3
dtype: int64

I would like to output simply the value 3. This behavoiur is quite strange, if you consider that the following very similar code is working:

>>> print(df['col1'].mean())

2.25

So two questions: why does this happen? How can I obtain the pure mode value as it happens for the mean?

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