Another option is library(plyr) ddply(df, "id", transform, valCS = cumsum(val))
Best, Ista On Mon, Mar 10, 2014 at 12:27 AM, Jim Lemon <j...@bitwrit.com.au> wrote: > In fact, I erred by summing both the year and the value, so i would > recommend Peter's (much less messy) solution. > > Jim > > > On 03/10/2014 02:57 PM, Peter Alspach wrote: >> >> Tena koe Philip >> >> An alternative to Jim's solution which seems to work and you may, or may >> not, find less messy: >> >> df<- read.table(text="id yr val >> a 1950 1 >> b 1950 10 >> a 1951 2 >> b 1952 3 >> c 1952 4 >> a 1954 5 >> b 1954 2 >> c 1954 3",header=TRUE) >> df1<- df[order(df$id, df$yr),] >> df1$valCS<- unlist(by(df1$val, df1$id, cumsum)) >> df1 >> >> If you need to get back to the original order you can sort by row.names. >> >> HTH .... >> >> Peter Alspach >> > > ______________________________________________ > 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. ______________________________________________ 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.
