Thanks Jim and David! It seems like both were great options. Both of your suggestions of pasting both IDs together worked well, keeping the pasting as a character is better. Though, Jim's example was interesting, it gave me the following error:
Error in `$<-.data.frame`(`*tmp*`, "coupleid", value = c(1L, 1L, 2L, 2L, : replacement has 123586 rows, data has 123631 Since this was a large dataframe, I don't know exactly where the error occurred. But, it seems like it was detecting missing values in some of the rows and after checking using the is.na() function, it didn't say that there were any missing values used (i.e. the new mID or sex). What do you guys think may be happening? Thanks, Carlos -- View this message in context: http://r.789695.n4.nabble.com/identify-duplicate-from-more-than-one-column-tp4035888p4037177.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.
