> -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of Jonathan > Sent: Thursday, May 20, 2010 3:25 PM > To: David Winsemius > Cc: r-help > Subject: Re: [R] intersect() without discarding duplicates? > > Thanks, but that doesn't quite work, since I'd want the result of b[b > %in% > a] to be symmetric with a[a%in%b] (so if there are two 2's in EACH > vector, > I'll get two 2's in the result, but if there are two 2's in only one > vector, > but one two in the other, the result will show only one 2. > > Consider: > > > a <- c(2,4,3) > > b<-c(6,6,5,2,2,8,4) > > > b[b %in% a] > [1] 2 2 4 > > > a[a%in%b] > [1] 2 4 > > The second answer is correct, but I can't predict which variable to put > in > which position in the statement, so I'd need them both to be correct. > > Best, > Jonathan >
I think you have misread the intersect documentation. Given your examples above intersect is what you in fact want. > a <- c(2,4,3) > b<-c(6,6,5,2,2,8,4) > intersect(a,b) [1] 2 4 Hope this is helpful, Dan Daniel J. Nordlund Washington State Department of Social and Health Services Planning, Performance, and Accountability Research and Data Analysis Division Olympia, WA 98504-5204 ______________________________________________ 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.