I have a data frame like this:
V1 V2 V3
AAA x 2
AAA x 5
AAA y 7
BBB y 7
BBB x 8
BBB y 3
I would like to sum up the values from V3 depending on V1 and get a data frame like that:
V1 V2 V3
AAA x 7
AAA y 7
BBB x 8
BBB y 10
Thanks for your help!