Sum cells by group in data frame

Question

I have a huge data frame that looks like this:

dados

and I want to sum the cells in column V9 according to V3; for example, I want to sum every V9 cell when V3=="Acrelândia".

`library(data.table);setDT(df)[,sum(V9),V3]` – Colonel Beauvel Jun 15 '15 at 06:31 — Colonel Beauvel, Jun 15 '15 at 06:31

score 1 · Answer 1 · answered Jun 15 '15 at 04:48

1

aggregate(V9~V3,df,sum);

answered Jun 15 '15 at 04:48

bgoldst

1 Answers1