Sorry for the double post, but this is probably faster: x[, colSums(x) != 0]
On Wed, Jan 14, 2009 at 8:22 PM, Gustavo Carvalho <gustavo.bi...@gmail.com> wrote: > You can also try this: > > x[,-(which(colSums(x) == 0))] > > Cheers, > > Gustavo. > > On Wed, Jan 14, 2009 at 8:01 PM, Anthony Dick <ad...@uchicago.edu> wrote: >> Hello- >> >> I would like to remove the columns of a matrix that contain all zeros. For >> example, from >> x<-matrix(c(1,5,3,2,1,4,0,0,0), ncol=3,nrow=3) >> >> I would like to remove the third column. However, because this is in a loop >> I need a way to first determine which columns are all zeros, and only then >> remove them. I.e., I don't know which column of x contains all zeros until >> after x is created. >> >> Thanks! >> >> Anthony >> >> -- >> Anthony Steven Dick, Ph.D. >> Post-Doctoral Fellow >> Human Neuroscience Laboratory >> Department of Neurology >> The University of Chicago >> 5841 S. Maryland Ave. MC-2030 >> Chicago, IL 60637 >> Phone: (773)-834-7770 >> Email: ad...@uchicago.edu >> Web: http://home.uchicago.edu/~adick/ >> >> ______________________________________________ >> 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.
