Hi Kathryn, another solution would be to use tapply function. So the code to create new1 vector would be:
a <- 1:8 fc <- c('g1','g1','g2','g3','g3','g3','g4','g4') # definitions of groups to sum over tapply(a,fc,sum) ivan On Fri, Jan 23, 2015 at 10:32 AM, Bert Gunter <gunter.ber...@gene.com> wrote: > If Jim's answer is not what you want, then I would say it is because > your question is too vague to be answered. In particular, how do you > specify the elements of the vector that are to be summed to create the > new vectors? ?tapply might then be relevant here, but that's just a > guess. > > -- Bert > > > > > > Bert Gunter > Genentech Nonclinical Biostatistics > (650) 467-7374 > > "Data is not information. Information is not knowledge. And knowledge > is certainly not wisdom." > Clifford Stoll > > > > > On Fri, Jan 23, 2015 at 12:45 AM, Kathryn Lord > <kathryn.lord2...@gmail.com> wrote: >> Dear R users, >> >> I have a quick quesiton. >> >> Here is a vector "a". >> >> a<- c(1,2,3,4,5,6,7,8). >> >> (In fact, I have a huge vector.) >> >> >> With "a", I'd like to create new vectors, for example, >> >> new1 = (1+2, 3, 4+5+6, 7+8) >> new2 = (1, 2+3+4+5+6+7, 8) >> new3 = (1+2+3+4+5+6+7, 8) >> >> >> How could I make the above vectors using R? >> >> >> Any suggestion will be greatly appreciated. >> >> Best, >> >> Kathryn Lord >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org 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. > > ______________________________________________ > R-help@r-project.org 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. ______________________________________________ R-help@r-project.org 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.