Hi, x<-matrix(0,80,ncol=1)
will create x matrix with all elements 0 (to be filled by the sums that you need) sum(y[y[,4]==1,5]) will calculate the sum of 5th column of y with 4th column=1 Similarly, sum(y[y[,4]==80,5]) will calculate the sum of 5th column of y with 4th column=80. You can adapt this to your case, with simple loops, etc. Hope this helps. Ozgur -- View this message in context: http://r.789695.n4.nabble.com/Summarizing-a-matrix-tp4632319p4632381.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
