Try this x%in%x[which(y)]
>From your example > x=c(1,2,3,4,4,5,6,7,8,9) > y=duplicated(x) > rbind(x,y) [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] x 1 2 3 4 4 5 6 7 8 9 y 0 0 0 0 1 0 0 0 0 0 > which(y) [1] 5 > x[which(y)] [1] 4 > x%in%x[which(y)] [1] FALSE FALSE FALSE TRUE TRUE FALSE FALSE FALSE FALSE FALSE Andrej -- Andrej Blejec National Institute of Biology Vecna pot 111 POB 141 SI-1000 Ljubljana SLOVENIA e-mail: andrej.ble...@nib.si URL: http://ablejec.nib.si tel: + 386 (0)59 232 789 fax: + 386 1 241 29 80 -------------------------- Organizer of Applied Statistics 2009 conference http://conferences.nib.si/AS2009 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of christiaan pauw > Sent: Thursday, May 14, 2009 8:17 AM > To: r-help@r-project.org > Subject: [R] Duplicates and duplicated > > Hi everybody. > I want to identify not only duplicate number but also the original > number > that has been duplicated. > Example: > x=c(1,2,3,4,4,5,6,7,8,9) > y=duplicated(x) > rbind(x,y) > > gives: > [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] > x 1 2 3 4 4 5 6 7 8 9 > y 0 0 0 0 1 0 0 0 0 0 > > i.e. the second 4 [,5] is a duplicate. > > What I want is the first and second 4. i.e [,4] and [,5] to be TRUE > > [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] > x 1 2 3 4 4 5 6 7 8 9 > y 0 0 0 1 1 0 0 0 0 0 > > I assume it can be done by sorting the vector and then checking is the > next > or the previous entry matches using > identical() . I am just unsure on how to write such a loop the logic of > which (I think) is as follows: > > sort x > for every value of x check if the next value is identical and return > TRUE > (or 1) if it is and FALSE (or 0) if it is not > AND > check is the previous value is identical and return TRUE (or 1) if it > is and > FALSE (or 0) if it is not > > Im i thinking correct and can some help to write such a function > > regards > Christiaan > > [[alternative HTML version deleted]] > > ______________________________________________ > 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.
