You did not provide any data, so I will take a guess at what it looks like:
> x <- matrix(sample(0:1, 100, TRUE), 10) > colnames(x) <- LETTERS[1:10] > x <- as.data.frame(x) > x A B C D E F G H I J 1 0 1 0 0 0 1 1 0 0 0 2 0 0 0 0 1 1 0 0 1 0 3 1 1 0 0 1 0 0 0 1 1 4 0 1 1 1 0 1 1 0 0 0 5 0 1 1 0 0 0 1 0 0 1 6 1 0 1 1 0 0 0 0 0 1 7 1 1 0 1 0 0 0 0 0 0 8 0 1 0 1 0 0 1 0 0 0 9 0 1 0 0 0 0 1 0 0 0 10 1 0 1 0 1 1 0 1 0 1 > x$match <- apply(x, 1, function(z) paste(colnames(x)[z == 1], collapse=",")) > > > x A B C D E F G H I J match 1 0 1 0 0 0 1 1 0 0 0 B,F,G 2 0 0 0 0 1 1 0 0 1 0 E,F,I 3 1 1 0 0 1 0 0 0 1 1 A,B,E,I,J 4 0 1 1 1 0 1 1 0 0 0 B,C,D,F,G 5 0 1 1 0 0 0 1 0 0 1 B,C,G,J 6 1 0 1 1 0 0 0 0 0 1 A,C,D,J 7 1 1 0 1 0 0 0 0 0 0 A,B,D 8 0 1 0 1 0 0 1 0 0 0 B,D,G 9 0 1 0 0 0 0 1 0 0 0 B,G 10 1 0 1 0 1 1 0 1 0 1 A,C,E,F,H,J > On Wed, Jan 7, 2009 at 1:28 PM, AllenL <allen.laroc...@gmail.com> wrote: > > Problem: > I have a data frame with 1s and 0s denoting presence/absence of species > (columns) for particular plot measurements (rows). What I want to do is make > a new column whose entries for each row is a list of the column names in > which a species is present (ie. for row one its entry might read: > "sp1","sp2", etc.). I've tried various functions etc. but can't seem to get > the syntax right/ the correct combination of functions. > Thanks in advance! > -Allen > > -- > View this message in context: > http://www.nabble.com/Another-newbie-question-tp21337371p21337371.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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ 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.
