Hi, You could also do:
mat1 <- matrix(NA,ncol=max(n),nrow=length(n)) mat1[cbind(rep(seq_along(n),n),seq_len(sum(n))- rep(cumsum(c(0L,n[-length(n)])),n))] <- y mat1 A.K. On Tuesday, February 25, 2014 10:34 AM, arun <[email protected]> wrote: Hi, One way would be: res <- t(sapply(split(y,rep(seq_along(n),n)),function(x) {if(length(x) < max(n)) c(x,rep(NA,max(n)-length(x))) else x})) A.K. Dear all, my question regards how to subset an existing vector in subvectors of different lengths and then create a matrix. See example below. I have vectors: y<-c(1,1,1,0,0,1,1) n<-c(3,2,2) and I'd like to create the matrix A of the following form: 1 1 1 0 0 NA 1 1 NA I'd like to "cut" y sequentially based on information in vector n, that is, generating 3 subvectors (the first with the first 3 elements of y, the second with the other 2 elements of y, and the last one with the latter 2 elements of y) and creating a matrix A (with dimensions, no.of rows=length(n), no. of col=max(n) and including NAs where necessary. Hope to have been clear. Bex ______________________________________________ [email protected] 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.
