Hi all, i have the following.. a <- data.frame(data = seq(1,10)) i have indices: x <- c(1, 5, 3, 9) y <- c(2, 7, 4, 10) I want the cumsum of a[1:2], a[5:7], a[3:4]... is there an elegant way to do it without any loop? Thanks! -- View this message in context: http://www.nabble.com/cumsum-list..-tp16025202p16025202.html Sent from the R help mailing list archive at Nabble.com.