Hi all, Sorry i forgot to mention there a species present in one matrix not in the other hence the problem i.e matrix 1 may have species E which isnt present in matrix 2 and matrix 2 may have species F not present in matrix 1.
Sorry for the lack of clarification in the original post! John On 17 Dec 2010, at 15:19, John Haart wrote: Hi, I have two matrices with a common field = species what i want to do is make a matrix that combines the data held in the other two based on the species name. I.e ( simple example) Matrix 1 - monocot SPECIES V1 A 2 B 3 C 4 D 5 Matrix 2 - PCAresults SPECIES V2 A 0.2 B 0.3 C 4.1 D 3.2 matrix 3 - What i want SPECIES V1 V2 A 2 0.2 B 3 0.3 C 4 4.1 D 5 3.2 my attempt has been this test <-monocot[which(monocot$SPECIES%in%PCAresults$SPECIES),] But this returns matrix with only those found in each but doesn't "import" the data from PCAresults Any help would be greatly appreciated John ______________________________________________ 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.