In this case you can simply do cumsum(a[x,]+a[y,])
Julian yoooooo wrote: > 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! > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
