Another option is which(y %in% x)
Dan Daniel J. Nordlund Washington State Department of Social and Health Services Planning, Performance, and Accountability Research and Data Analysis Division Olympia, WA 98504-5204 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- > project.org] On Behalf Of Pascal Oettli > Sent: Tuesday, February 12, 2013 2:21 AM > To: Robert Latest > Cc: r-help@r-project.org > Subject: Re: [R] Is there a neat R trick for this? > > Hello, > > ?match > > > x <- c(4,5,6) > > y <- c(10,1,5,12,4,13,14) > > match(x,y) > [1] 5 3 NA > > Hope this helps, > Pascal > > > Le 12/02/2013 19:09, Robert Latest a écrit : > > Hello all, > > > > given two vectors X and Y I'd like to receive a vector Z which > > contains, for each element of X, the index of the corresponding > > element in Y (or NA if that element isn't in Y). > > > > Example: > > > > x <- c(4,5,6) > > y <- c(10,1,5,12,4,13,14) > > > > z <- findIndexIn(x, y) > > z > > [1] 5 3 NA > > > > 1st element of z is 5, because the 1st element of x is at the 5th > position in y > > 2nd element of z is 3, because the 2nd element of x is at the 3rd > position in y > > 3rd element of z is NA, because the 3rd element of x is not in y > > > > Of course I can write the function findIndexIn() using a for loop, > but > > in 80% of cases when I felt the urge to use "for" in R it turned out > > that there was already some builtin operator or function that did the > > trick. > > > > Suggestions, anyone? > > Thanks, > > > > robert > > > > ______________________________________________ > > 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. ______________________________________________ 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.