Hi, I believe the function you are looking for is:
which("yourdata" == 0, arr.ind = T) The "arr.ind" parameter in the "which" function will return you a matrix with row, column indices for where there are 0's in your dataset. set.seed(6584) data <- matrix(sample(c(0,1), 36, replace = T), nc = 6, dimnames = list(c(paste("c",1:6, sep = "")), paste("r", 1:6, sep = ""))) data # r1 r2 r3 r4 r5 r6 #c1 1 1 0 1 0 1 #c2 1 0 0 0 1 0 #c3 1 0 1 0 0 1 #c4 1 1 0 0 0 1 #c5 0 0 0 1 0 1 #c6 0 0 1 1 1 0 array_indices <- which(data == 0, arr.ind = T) array_indices # row col #c5 5 1 #c6 6 1 #c2 2 2 #c3 3 2 #c5 5 2 #c6 6 2 #c1 1 3 #c2 2 3 #c4 4 3 #c5 5 3 #c2 2 4 #c3 3 4 #c4 4 4 #c1 1 5 #c3 3 5 #c4 4 5 #c5 5 5 #c2 2 6 #c6 6 6 cbind(row = rownames(data)[array_indices[,1]], col = colnames(data)[array_indices[,2]]) The last command will get you rownames and colnames from your dataset. Richard On Fri, Sep 20, 2013 at 4:40 PM, John Kane <jrkrid...@inbox.com> wrote: > Once you learn to use dput() I am sure someone will be happy to help you. > > > http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example > > John Kane > Kingston ON Canada > > >> -----Original Message----- >> From: elaine.kuo...@gmail.com >> Sent: Sat, 21 Sep 2013 07:14:38 +0800 >> To: r-help@r-project.org >> Subject: [R] search species with all absence in a presence-absence matrix >> >> Dear list >> >> >> >> I have a matrix composed of islandID as rows and speciesID as columns. >> >> IslandID: Island A, B, C?.O (15 islands in total) >> >> SpeciesID: D0001, D0002, D0003?.D0100 (100 species in total) >> >> >> >> The cell of the matrix describes presence (1) or absence (0) of the >> species >> in an island. >> >> >> >> Now I would like to search the species with absence (0) >> >> in all the islands (Island A to Island O.) >> >> >> >> Please kindly advise the R code for the search purpose. >> >> Thank you. >> >> >> >> Elaine >> >> [[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. > > ____________________________________________________________ > FREE 3D EARTH SCREENSAVER - Watch the Earth right on your desktop! > > ______________________________________________ > 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.