If A and B are first and second matrix respectively then try: rowSums(inner(A, t(B), identical))
where the generalized inner product, inner, is defined in this post: http://tolstoy.newcastle.edu.au/R/e4/help/08/08/19562.html On Thu, Jul 2, 2009 at 8:27 AM, dreamworx<andy_wools...@hotmail.com> wrote: > > I have a matrix such as this, > > [,1] [,2] [,3] > [1,] 1 1 2 > [2,] 2 5 5 > > and a larger matrix such as this, > > a b > [1,] 1 5 > [2,] 2 5 > [3,] 4 9 > [4,] 5 8 > [5,] 7 8 > [6,] 7 10 > [7,] 9 10 > > what I want to do is check the number of times the columns in the first > matrix appear as rows in the second matrix. So for instance in this example > 1,5 and 2,5 appear in both so I'd want R to return the number 2. Is there a > function to do this? > -- > View this message in context: > http://www.nabble.com/matching-rows-in-matrices-tp24305831p24305831.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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.
