Assuming the 400 numeric variables are integers this will be simpler if you can identify the columns to be converted to factors as a block of column numbers (e.g. 1:400, or 401:800)
# Create some data X <- data.frame(matrix(nrow=20, ncol=20)) for (i in 1:10) X[,i] <- round(runif(20, .5, 5.5), 0) for (i in 11:20) X[,i] <- rnorm(20) str(X) # structure of X # convert numbers to factors for the first 10 columns X2 <- X for (i in 1:10) X2[,i] <- factor(X[,i]) str(X2) ---------------------------------------------- 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 ya > Sent: Tuesday, May 08, 2012 12:01 PM > To: r-help > Subject: [R] convert 400 numeric variables to categorical together > > > > > > > Hi Jim and Michael, > > Thank you very much for replying. > > Here is the information about my data. I have a data frame, including > more than 800 variables(columns) and 30000 cases(rows).400 of those > variables are categorical variables. I used to use Rcmdr to convert > variables, however, when the number of variables I need to convert > getting more, I need to keep left clicking mouse to confirm the > conversion (400 times) because as.factor() can only convert 1 variable > at a time. So I am thinking if there is any faster way. Thank you very > much. > > Best regards, > > ya > > > > ya > > From: R. Michael Weylandt > Date: 2012-05-08 19:35 > To: xinxi813 > CC: r-help > Subject: Re: [R] convert 400 numeric variables to categorical together > How are they arranged currently? And should they be all one set of > levels or different factor sets? > > Michael > > On Tue, May 8, 2012 at 12:32 PM, ya <xinxi...@163.com> wrote: > > Hi everyone, > > > > Is there anyway I can convert more than 400 numeric variables to > categorical variables simultaneously? > > > > as.factor() is really slow, and only one at a time. > > > > Thank you very much. > > > > ya > > [[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. > [[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.
