If speed is a consideration,availing yourself of the built-in pmax() function via
do.call(pmax,data.frame(yourMatrix)) will be considerably faster for large matrices. If you are puzzled by why this works, it is a useful exercise in R to figure it out. Hint:The man page for ?data.frame says: "A data frame is a list of variables of the same length with unique row names, given class 'data.frame'." Cheers, Bert Bert Gunter Genentech Nonclinical Statistics -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Wacek Kusnierczyk Sent: Saturday, March 28, 2009 5:22 PM To: Ana M Aparicio Carrasco Cc: r-help@r-project.org Subject: Re: [R] Matrix max by row Ana M Aparicio Carrasco wrote: > I need help about how to obtain the max by row in a matrix. > For example if I have the following matrix: > 2 5 3 > 8 7 2 > 1 8 4 > > The max by row will be: > 5 > 8 > 8 > matrix(apply(m, 1, max), nrow(m)) vQ ______________________________________________ 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.