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.
