building on the previous responses, does this give you what you want: > x A B 1 1 1 2 2 NA 3 NA NA 4 NA 4 > # determine where the NAs are > row.na <- apply(x, 1, is.na) > # now convert to list of columns with NAs > apply(row.na, 2, function(a) paste(colnames(x)[a], collapse = ',')) [1] "" "B" "A,B" "A" > >
On Mon, Jan 17, 2011 at 5:01 AM, Johannes Graumann <[email protected]> wrote: > Hi, > > What is an efficient way to take this DF > > data.frame(A=c(1,2,NA,NA),B=c(1,NA,NA,4)) > > and get > c(NA,"TWO","BOTH","ONE") > > as the result, where NA corresponds to a row without "NA"s, TWO indicates NA > in the second and ONE in the first column. > > Thanks for any pointers. > > Joh > > ______________________________________________ > [email protected] 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 Data Munger Guru What is the problem that you are trying to solve? ______________________________________________ [email protected] 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.
