Keep certain columns in a pandas DataFrame, deleting everything else

If you have a list of columns you can just select those:

In [11]: df
Out[11]:
   1  2  3  4  5  6
A  x  x  x  x  x  x
B  x  x  x  x  x  x
C  x  x  x  x  x  x

In [12]: col_list = [3, 5]

In [13]: df = df[col_list]

In [14]: df
Out[14]:
   3  5
A  x  x
B  x  x
C  x  x