on 11/26/2008 07:11 AM axionator wrote: > Hi all, > I have an unkown number of vectors (>=2) all of the same length. Out > of these, I want to construct a new one as follows: > having vectors u,v and w, the resulting vector z should have entries: > z[1] = u[1], z[2] = v[1], z[3] = w[1] > z[4] = u[2], z[5] = v[2], z[6] = w[2] > ... > i.e. go through the vector u,v,w, take at each time the 1st, 2sd, ... > elements and store them consecutively in z. > Is there an efficient way in R to do this? > > Thanks in advance > Armin
Is this what you want? u <- 1:10 v <- 11:20 w <- 21:30 z <- as.vector(rbind(u, v, w)) > z [1] 1 11 21 2 12 22 3 13 23 4 14 24 5 15 25 6 16 26 7 17 27 8 [23] 18 28 9 19 29 10 20 30 Essentially, we are creating a matrix from the 3 vectors: > rbind(u, v, w) [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] u 1 2 3 4 5 6 7 8 9 10 v 11 12 13 14 15 16 17 18 19 20 w 21 22 23 24 25 26 27 28 29 30 Then coercing that to a vector, taking advantage of the way in which matrix elements are stored. HTH, Marc Schwartz ______________________________________________ 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.
