Thanks for your help guys. I was refering to the variables the wrong way. This worked for me:
idx <- !duplicated(detail2[,c("TDATE","FIRM","CM","BRANCH", "BEGTIME", "ENDTIME","OTYPE","OCOND", "ACCTYP","OSIDE","SHARES","STOCKS", "STKFUL")]) detail3 <- detail2[idx,] -- View this message in context: http://r.789695.n4.nabble.com/Deduping-in-R-by-multiple-variables-tp4641778p4641854.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.