sapply() is not the right tool. It operates on a list, and a matrix is not a list (at least not treated as you'd expected it to be). It would have sort of worked if tempMatrix were a data frame instead of a matrix.
Try something like: colSums(tempMatrix[, seq(1, ncol(tempMatrix), by=2)] > 0) Andy From: [EMAIL PROTECTED] > > I've tried and give up. I have a matrix of say 200 columns > and 400 rows. > > For each odd ( or even i suppose if i wanted to )column, I > want to know the number of rows in which the value is greater > than zero. > > So, I did sapply(tempMatrix,2,function(x) sum( x > 0 )) > > this almost works but i don't know how to tell it to only do > the odd columns. my guess is , like everything else in R, > this is possible. Thanks. > > ______________________________________________ > [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 > > ______________________________________________ [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
