my.data$z <- cumsum(my.data$y) Yes, the function you need is even in your message subject.
> On Dec 8, 2014, at 12:18 AM, Ragia Ibrahim <[email protected]> wrote: > > Hi, > Kindly I had a data frame looks like this > x y > 1 3 > 2 2 > 3 1 > 4 3 > and I want to add column z that sum cumulativly like this > x y z > 1 3 3 > 2 2 5 > 3 1 6 > 4 3 9 > > how to do this? > Regards > Ragia > > [[alternative HTML version deleted]] > > ______________________________________________ > [email protected] mailing list -- To UNSUBSCRIBE and more, see > 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. Don McKenzie Research Ecologist Pacific Wildland Fire Sciences Lab US Forest Service Affiliate Faculty School of Environmental and Forest Sciences University of Washington [email protected] ______________________________________________ [email protected] mailing list -- To UNSUBSCRIBE and more, see 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.
