Hi I am not sure I understand correctly. In the sample dataframe you posted, the values in columns are different so based on what you did write I aasume that
apply(df,1, paste, collapse="") gives you third variable combined from those 2 variables. If you want to select non NA value from any variable, which one will you select when there is no NA in some row? Regards Petr > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of Simon Kiss > Sent: Tuesday, September 11, 2012 4:57 PM > To: r-help@r-project.org > Subject: [R] Combine two variables > > Hi: > I have two variables in a data frame that are the results of a wording > experiment in a survey. I'd like to create a third variable that > combines the two variables. Recode doesn't seem to work, because it > just recodes the first variable into the third, then recodes the second > variable into the third, overwriting the first recode. I can do this > with a rather elaborate indexing process, subsetting the first column > and then copying the data into the second etc. But I'm looking for a > cleaner way to do this. The data frame looks like this. > > > df<-data.frame(var1=sample(c('a','b','c',NA),replace=TRUE, size=100), > var2=sample(c('a','b','c',NA),replace=TRUE,size=100)) > > df<-subset(df, !is.na(var1) |!is.na(var2)) > > As you can see, if one variable has an NA, then the other variable has > a valid value, so how do I just combine the two variables into one? > Thank you for your assistance. > Simon Kiss > > ______________________________________________ > 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.