Well, strictly speaking, this is still doing it "one variable at a time." The interpreted loop is hidden, but it's still happening.
A loop free but clumsier approach is: y <- data.frame(matrix(as.character(x),nrow = nrow(x))) ## Note also that the original column names will be lost and will have to be added to the data frame. It would also not surprise me if for such a small matrix that Rui's version were faster. -- Bert On Fri, Oct 19, 2012 at 7:07 AM, Rui Barradas <ruipbarra...@sapo.pt> wrote: > Hello, > > Try the following. > > x <- matrix(sample(0:1, 12, TRUE), ncol = 4) > y <- data.frame(apply(x, 2, factor)) > str(y) > > Hope this helps, > > Rui Barradas > Em 19-10-2012 12:04, brunosm escreveu: >> >> Hi all, >> >> I have a matrix with 100 variables: each variable as a value of 0 or 1. >> >> What i want to do is convert this matrix to a data.frame but convert all >> the >> variables to factors (0 and 1) also. >> >> I know i can do this one variable a time but i have 100 variables... >> >> Any easy way of doing this?? >> >> Thanks a lot, >> >> Bruno >> >> >> >> -- >> View this message in context: >> http://r.789695.n4.nabble.com/Matrix-to-data-frame-with-factors-tp4646730.html >> Sent from the R help mailing list archive at Nabble.com. >> >> ______________________________________________ >> 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. -- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm ______________________________________________ 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.