I may be mistaken, but I don't think that's possible or even should be possible. A matrix is m x n, where m and n are (kind of fixed) integers. You cannot have a matrix where m(1) to m(n) (the row lengths) vary. If you want to do this, you have to use a list instead (I believe).
As a poor workaround you could fill an m x n matrix with NAs or 0s (where n is the anticipated maximum length among all rows) and then fill the rows with the values. However, this is dirty as you will not be able to distinguish true NAs or 0s at the end of a row from the ones you have used to fill the dummy matrix in the first place; so the list is really the way to go. x1=c(1,2,3) x2=c(4,5,6) y1=c(0,1,2,3) y2=c(4,5,6,7) myList=list(x1,y1) myList myList[[1]]=append(myList[[1]],x2) myList[[2]]=append(myList[[2]],y2) myList HTH, Daniel ------------------------- cuncta stricte discussurus ------------------------- -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Trafim Vanishek Sent: Monday, April 05, 2010 3:21 PM To: r-help@r-project.org Subject: [R] Matrix elements are vectors Dear all, My question how is it possible to define a matrix A with 10 rows 1 column, so that its elements are vectors of undefined length. I need to have a possibility later to add elements like A[1,1] <- c(A[1,1],3,4,5) Thanks a lot for the help! [[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. ______________________________________________ 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.
