HI, Try this:
a <- data.frame( col1 = c(1,2,3,3,4)) a<-within(a, duplicate<-c(0,ifelse(diff(a$col1)==0,1,0))) a col1 duplicate 1 1 0 2 2 0 3 3 0 4 3 1 5 4 0 A.K. ----- Original Message ----- From: Jeff <r...@jp.pair.com> To: r-help@r-project.org Cc: Sent: Wednesday, July 25, 2012 4:05 PM Subject: [R] Simple question on finding duplicates I'm trying to find duplicate values in a column of a data frame. For example, dataframe (a) below has two 3's. I would like to mark each value of each row as either not being a duplicate of the one before (0), or as a duplicate (1) - for example, as in dataframe (b). In SPSS, I would simply compare each value to it's "lagged" value, but I can't figure out how to do this with R. Can someone point me in the right direction? Thanks a <- data.frame( col1 = c(1,2,3,3,4)) b <- data.frame( col1 = c(1,2,3,3,4), duplicate = c(0,0,0,1,0)) ______________________________________________ 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.
