I have a data frame that looks like this:
Index Measure Tom Harry Mary
0 A 10 5 9
1 B 4 4 8
2 A 11 5 7
3 B 2 3 6
4 A 8 5 5
5 B 4 7 5
6 A 10 5 4
7 B 5 5 3
I basically need it to sum the values for each person for the rows where Measure = A. So for Tom, it would be 39, Harry would be 20 & Mary would be 25. Thanks in advance!