length(intersect(a, b))
On Sat, Apr 16, 2011 at 8:04 PM, Jim Silverton <jim.silver...@gmail.com> wrote: > I have two columns and I want to count hwo many pairs I have of the same > element. For example. If I have > a = c(1,2,3,4,5) > b= c(12, 1, 34, 2, 5, 0, 10, 100, 11) > It should return 3 (since 1, 2 and 5 occur in both columns). > Columns need not be of the same length. > > -- > Thanks, > Jim. > > [[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.
