Re: [R] Getting indeices of intersecting elements.
> -Original Message- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Praveen Surendran > Sent: Wednesday, October 14, 2009 9:15 AM > To: r-help@r-project.org > Subject: [R] Getting indeices of intersecting elements. > > Hi, > > Is there a command to get the indices of intersecting elements of two > vectors as intersect() will give the elements and not its indices. intersect() uses match() to do that. match(x,y,nomatch) gives the indices of elements of y that elements of x match and match(y,x,nomatch) gives the indices of the elements of x that elements of y match. In each case, the unmatched elements are marked by the value in nomatch. E.g. > x<-letters[1:5] > y<-letters[(1:5)*2] > x [1] "a" "b" "c" "d" "e" > y [1] "b" "d" "f" "h" "j" > match(y,x,nomatch=0) # x[c(2,4)] are in y [1] 2 4 0 0 0 > match(x,y,nomatch=0) # y[c(1,2)] are in x [1] 0 1 0 2 0 (If the second argument contains duplicates the index is for the first of them.) Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > Thanks in advance. > > > > Praveen Surendran > > School of Medicine and Medical Sciences > > University College Dublin > > Belfield, Dublin 4 > > Ireland. > > > [[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.
Re: [R] Getting indeices of intersecting elements.
On Oct 14, 2009, at 12:15 PM, Praveen Surendran wrote: Hi, Is there a command to get the indices of intersecting elements of two vectors as intersect() will give the elements and not its indices. ?which samp1 <- sample(seq(3,198, by=3), 20); samp2 <- sample(seq(3,198, by=3), 20) int <- intersect(samp1, samp2) int #[1] 48 87 9 159 36 6 39 105 which(seq(3,198, by=3) %in% int) #[1] 2 3 12 13 16 29 35 53 Thanks in advance. Praveen Surendran School of Medicine and Medical Sciences University College Dublin Belfield, Dublin 4 Ireland. [[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. David Winsemius, MD Heritage Laboratories West Hartford, CT __ 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] Getting indeices of intersecting elements.
Hi, Is there a command to get the indices of intersecting elements of two vectors as intersect() will give the elements and not its indices. Thanks in advance. Praveen Surendran School of Medicine and Medical Sciences University College Dublin Belfield, Dublin 4 Ireland. [[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.
