Sum every nth points

Question

I have a vector and I need to sum every n numbers and return the results. This is the way I plan on doing it currently. Any better way to do this?

Answer 1

One way is to use rollapply from zoo:

rollapply(v, width=n, FUN=sum, by=n)
# [1]  55 155 255 355 455 555 655 755 855 955

And in case length(v) is not a multiple of n:

v <- 1:92

rollapply(v, width=n, FUN=sum, by=n, partial=T, align="left")
# [1]  55 155 255 355 455 555 655 755 855 183