how to concatenate factor vectors?
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.berton at gene.com> To: Jorge I Velez <jorgeivanvelez at gmail.com> Cc: r-help at r-project.org; sds at 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
<jorgeivanvelez at 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)
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______________________________________________ R-help at 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 at 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.