Dear Ted, you could try something like,
dat <- data.frame(V1=sample(LETTERS[1:3], 10, rep=T), V2=sample(letters[1:3], 10, rep=T)) mat <- apply(as.matrix(dat), 1, function(x) paste(x, collapse="")) dat$glue <- factor(mat) dat I hope this helps. Best, Dimitris ---- Dimitris Rizopoulos Doctoral Student Biostatistical Centre School of Public Health Catholic University of Leuven Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/16/396887 Fax: +32/16/337015 Web: http://www.med.kuleuven.ac.be/biostat/ http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm ----- Original Message ----- From: "Ted Harding" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, June 15, 2004 10:26 AM Subject: [R] "Glueing" factors together > Hi folks, > > Suppose I have a series of cases each with categorical > factors A, B. > > What is the best way to "glue" A and B together into a single > factor? For example, given > > A0 B1 ... > A1 B1 ... > A0 B2 ... > A1 B0 ... > A0 B0 ... > A1 B2 ... > > then I'd like to end up with a single factor with levels > > A0B0, A0B1, A0B2, A1B0, A1B1, A1B2 > > according to all the combinations which actually occur in the > data (e.g. if (A1,B2) did not occur in the data, then A1B2 would > not be a level in the resulting "glued" factor). > > I can see clumsy and tedious ways involving manipulating strings, > paste(), etc.; but I'm sure it must be possible more elegantly. > > With thanks, and best wishes to all, > Ted. > > > -------------------------------------------------------------------- > E-Mail: (Ted Harding) <[EMAIL PROTECTED]> > Fax-to-email: +44 (0)870 167 1972 > Date: 15-Jun-04 Time: 09:26:06 > ------------------------------ XFMail ------------------------------ > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://www.stat.math.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
