> f <- function(n){as.vector(sweep(matrix(4:6,nrow=3,ncol=n),2,seq (from=0,by=9,len=n),"+"))} > f(10) [1] 4 5 6 13 14 15 22 23 24 31 32 33 40 41 42 49 50 51 58 59 60 67 68 69 76 77 78 85 86 87 >
HTH rksh On 30 Jan 2007, at 14:29, Adrian DUSA wrote: > Dear list, > > This should be a simple one, I just cannot see it. > I need to generate a sequence of the form: > 4 5 6 13 14 15 22 23 24 > > That is: starting with 4, make a 3 numbers sequence, jump 6, then > another 3 > and so on. > I can create a whole vector with: > myvec <- rep(rep(c(F, T, F), rep(3, 3)), 3) > > Then see which are TRUE: > which(myvec) > [1] 4 5 6 13 14 15 22 23 24 > > > I'd like to avoid creating the whole vector if possible; for very > large ones > it can be time consuming. There should be a way to only create the > proper > indexes... > > Thanks for any hint, > Adrian > > -- > Adrian Dusa > Romanian Social Data Archive > 1, Schitu Magureanu Bd > 050025 Bucharest sector 5 > Romania > Tel./Fax: +40 21 3126618 \ > +40 21 3120210 / int.101 > > ______________________________________________ > R-help@stat.math.ethz.ch 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. -- Robin Hankin Uncertainty Analyst National Oceanography Centre, Southampton European Way, Southampton SO14 3ZH, UK tel 023-8059-7743 ______________________________________________ R-help@stat.math.ethz.ch 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.