If a and b are your matrices of common row length, unique() can solve it: unique(cbind(a,b), MARGIN=2)
Eric -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Giuseppe Paleologo Sent: Wednesday, August 06, 2008 3:33 PM To: r-help@r-project.org Subject: [R] Union of columns of two matrices I was posed the following problem/teaser: given two matrices, come up with an "elegant" (=fast & short) function that returns a matrix with all and only the non-duplicated columns of both matrices; the column order does not matter. In essence, a matrix equivalent of union(x,y), where x and y are vectors. I could not come with anything nice. Any ideas? Giuseppe -- Giuseppe A. Paleologo :: Email: [EMAIL PROTECTED] :: AOL: gappy3000 :: Skype :: gappy3000 :: Gtalk: paleologo :: Mobile: 917.331.3497 fact: 2^32,582,657-1 is a prime [[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.
