Cumulative total by group

Question

For the following dataset:

d = data.frame(date = as.Date(as.Date(\'2015-01-01\'):as.Date(\'2015-04-10\'), origin = \"1970-01-01\"),
               group = re         


        

Answer 1

If you just want cumulative sums per group, then you can do

transform(d, new=ave(value,group,FUN=cumsum))

with base R.