Can you say a little more about what you mean "it does not work"? I'd guess you have a regular expression mistake and are probably getting more columns than desired, but without an example, it's hard to be certain.
Use dput() and head() to give a small cut-and-paste-able example. Michael On Mon, Aug 22, 2011 at 10:33 AM, Jay <josip.2...@gmail.com> wrote: > Hi, > > Let's say that I have a set of column names that begin with the string > "Xyz". How do I extract these specific columns? I tried to do the > following: > > dataframe1[,grep("Xyz",colnames(dataframe1))] > > But it does not work. What is wrong with my expression? > > ______________________________________________ > 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. > [[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.