Hi, May be this also works: a <- factor(c(1,3,5)) b <- factor(c(5,7)) f1<-as.numeric(c(as.character(a),as.character(b))) lev<-as.numeric(c(levels(a),setdiff(levels(b),levels(a)))) f2<-factor(f1,levels=lev) f2 #[1] 1 3 5 5 7 #Levels: 1 3 5 7
a1<-factor(5:1,levels=1:9) b1<-factor(9:1,levels=1:9) f<-as.numeric(c(as.character(a1),as.character(b1))) lev1<-as.numeric(c(levels(a1),setdiff(levels(b1),levels(a1)))) f3<-factor(f,levels=lev1) f3 # [1] 5 4 3 2 1 9 8 7 6 5 4 3 2 1 #Levels: 1 2 3 4 5 6 7 8 9 A.K. ----- Original Message ----- From: Bert Gunter <gunter.ber...@gene.com> To: Jorge I Velez <jorgeivanve...@gmail.com> Cc: r-help@r-project.org; s...@gnu.org Sent: Thursday, October 18, 2012 2:21 AM Subject: Re: [R] how to concatenate factor vectors? No. You need to test more carefully. > a <- factor(c(1,3,5)) > b <- factor(c(5,7)) > c(a,b) [1] 1 2 3 1 2 > lev <- sort(unique(f <- c(a,b))) > f <- factor(f,levels=lev) > f [1] 1 2 3 1 2 Levels: 1 2 3 ## but > unlist(list(a,b),use.names=FALSE) [1] 1 3 5 5 7 Levels: 1 3 5 7 However, Is level "5" in 'a' the same as level "5" in 'b' ? The OP fails to specify, and there's no reason to assume so. So I would say clarification is required before any answer can be given. -- Bert On Wed, Oct 17, 2012 at 10:43 PM, Jorge I Velez <jorgeivanve...@gmail.com> wrote: > Hi Sam, > > Perhaps the following? > >> a <- factor(5:1,levels=1:9) >> b <- factor(9:1,levels=1:9) >> lev <- sort(unique(f <- c(a, b))) >> f <- factor(f, levels = lev) >> str(f) > Factor w/ 9 levels "1","2","3","4",..: 5 4 3 2 1 9 8 7 6 5 ... > > HTH, > Jorge.- > > > On Thu, Oct 18, 2012 at 3:44 PM, Sam Steingold <> wrote: > >> How do I concatenate two vectors of factors? >> --8<---------------cut here---------------start------------->8--- >> > a <- factor(5:1,levels=1:9) >> > b <- factor(9:1,levels=1:9) >> > str(c(a,b)) >> int [1:14] 5 4 3 2 1 9 8 7 6 5 ... >> > str(unlist(list(a,b),use.names=FALSE)) >> Factor w/ 9 levels "1","2","3","4",..: 5 4 3 2 1 9 8 7 6 5 ... >> --8<---------------cut here---------------end--------------->8--- >> so, unlist(list()) works. >> is there a better way or is this how this is supposed to be done? >> Thanks! >> -- >> Sam Steingold (http://sds.podval.org/) on Ubuntu 12.04 (precise) X >> 11.0.11103000 >> http://www.childpsy.net/ http://honestreporting.com >> http://think-israel.org http://thereligionofpeace.com >> http://mideasttruth.com >> (lisp programmers do it better) >> >> ______________________________________________ >> 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. -- 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. ______________________________________________ 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.
