Assuming you mean that the column is constant so that the sd is 0 test <- matrix(rnorm(50), nrow=10, ncol=5) test[,2] <- 1 test[,4] <- 2 # test[,which(apply(test, 2, sd) > 0)] could fail on rounding errors Test2 <- test[, which(apply(test, 2, sd) > 1e-10)]
---------------------------------------------- David L Carlson Associate Professor of Anthropology Texas A&M University College Station, TX 77843-4352 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of Chris Burns > Sent: Wednesday, May 23, 2012 7:45 PM > To: r-help@r-project.org > Subject: [R] Exclude when sd=0 > > How do I trim a matrix to exclude columns that have no standard > deviation? > > Thanks, > > Chris > > [[alternative HTML version deleted]] > > ______________________________________________ > 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.
