Hi, I have two matrices as follow: matrix A =
a=matrix(c(c("abc","abc","bcd","bcd","bce","bce"),c("a1","d2","d1","d2","a1","a2")),6,2) and matrix B which contains pair of values : b=matrix(c(c("a1","a1"),c("a2","d2")),2,2) In short, I wish to find out pairs of values in matrix a[,2] having same value in a[,1], which occur as a row in matrix b, so that the output becomes : abc bce, or even better abc a1 d2 bce a1 a2 How can I do that? cheers, Joshi ______________________________________________ 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.