Thanks. That's what I want. Sorry for the typo:) Feng
On Mon, Sep 13, 2010 at 11:42 AM, Ted Harding <ted.hard...@manchester.ac.uk>wrote: > On 13-Sep-10 09:19:21, Feng Li wrote: > > Dear R, > > I have a vector, say a = c(1,2,4,5,6,8). Can I generate a vector > > or array (2-by-3-by-3) of this form > > c(1,2,1,2,1,2,4,5,4,5,4,5,6,8,6,8,6,8) > > in which every two elements in "a" have been repeated twice? > > > > I am to stupid today and could not figure this simple question out... > > Many many thanks! > > > > Feng > > A possible solution (somewhat generalisable): > > a <- c(1,2,4,5,6,8) > Reps <- 3 > > pairs <- matrix(a,nrow=2) > as.vector(pairs[,rep(c(1,2,3),each=Reps)]) > # [1] 1 2 1 2 1 2 4 5 4 5 4 5 6 8 6 8 6 8 > > (By the way, you have 3 repetitions but wrote "twice" -- I assume > you meant "thrice" but the above generalises to 2 repetitions ... :) > > Ted. > > -------------------------------------------------------------------- > E-Mail: (Ted Harding) <ted.hard...@manchester.ac.uk> > Fax-to-email: +44 (0)870 094 0861 > Date: 13-Sep-10 Time: 10:42:46 > ------------------------------ XFMail ------------------------------ > -- Feng Li Department of Statistics Stockholm University 106 91 Stockholm, Sweden http://feng.li/ [[alternative HTML version deleted]] ______________________________________________ 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.
