On Sun, Jul 20, 2008 at 4:16 PM, Ralph S. <[EMAIL PROTECTED]> wrote: > > Hi, > > I am trying to calculate the sum for each occurrence of the level of a factor > in a very large matrix. In addition, I want to save that sum together with > the information of the level of the factor and the level of a second factor. > > My matrix looks like this: > > x<-matrix(c(1,1,1,2,2,3,3,1,1,7,7,7,4,4,2,2,7,7,1,1,1,1,1,1,2,5,5),9,3) > > I want to sum according to the levels in the first column and save the sum > with the information of the level in the first and the second column in a new > matrix. > > That is, I want output in the matrix of form: > > 1 7 3 > 2 4 2 > 3 2 3 > 1 7 10 >
Why that and not: 1 7 13 2 4 2 3 2 3 ? Hadley -- http://had.co.nz/ ______________________________________________ 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.
