Minor correction: duplicate <- ifelse(c(0, a$col[-length(a$col)])==a$col, 1, 0)
------- David > -----Original Message----- > From: David L Carlson [mailto:dcarl...@tamu.edu] > Sent: Wednesday, July 25, 2012 3:23 PM > To: 'Jeff'; 'r-help@r-project.org' > Subject: RE: [R] Simple question on finding duplicates > > duplicate <- ifelse(c(0, a$col[-length(a$col)])==c(a$col), 1, 0) > > ---------------------------------------------- > David L Carlson > Associate Professor of Anthropology > Texas A&M University > College Station, TX 77843-4352 > > > > -----Original Message----- > > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > > project.org] On Behalf Of Jeff > > Sent: Wednesday, July 25, 2012 3:06 PM > > To: r-help@r-project.org > > 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.
