I have a dataframe like this:
A B C D
---------------
1 a 0 1
2 4 0 3
3 a 0 4
4 a 4 5
5 t 3 9
I would like to fetch out the column C
alone,whenever the value in A
is a
.
So I should get :
C
--
0
0
4
How to get it done?