Another newbie question
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.larocque at 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.
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Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve?