Hi I have another question concerning matrices: I have two matrices:
> b <- matrix(1:25,5,5,byrow=T) > b [,1] [,2] [,3] [,4] [,5] [1,] 1 2 3 4 5 [2,] 6 7 8 9 10 [3,] 11 12 13 14 15 [4,] 16 17 18 19 20 [5,] 21 22 23 24 25 and > d <- matrix(1:4,2,2,byrow=T) > d [,1] [,2] [1,] 1 2 [2,] 3 4 > and I want to "add" d to b in such a way that I specify one cell in matrix b , e.g. [1,2]: [,1] [,2] [,3] [,4] [,5] [1,] 1 2+1 3+2 4 5 [2,] 6 7+3 8+4 9 10 [3,] 11 12 13 14 15 [4,] 16 17 18 19 20 [5,] 21 22 23 24 25 Is there an easy way of doing this, apart from iterating through the matrix d? Also, when I use > apply(d, c(1,2), function(x) {}) is there a way of knowing the column anr row which the element x is from, or o I have to use for loops for that? Thanks in advance, Rainer ______________________________________________ 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.