On Mon, Jul 30, 2012 at 6:00 PM, jim holtman <jholt...@gmail.com> wrote: > try this: > >> (x <- rep(letters,2)) > [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" > "q" "r" "s" "t" "u" "v" "w" > [24] "x" "y" "z" "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" > "n" "o" "p" "q" "r" "s" "t" > [47] "u" "v" "w" "x" "y" "z" >> values <- c("aa", "a", "b", NA, "d", "zz") >> repl <- c("aa", "A", "B", NA, "D", "zz") >> (repl.tab <- cbind(values, repl)) > values repl > [1,] "aa" "aa" > [2,] "a" "A" > [3,] "b" "B" > [4,] NA NA > [5,] "d" "D" > [6,] "zz" "zz" >> indx <- match(x, repl.tab[, 1], nomatch = 0) >> x[indx != 0] <- repl.tab[indx, 2] >> x > [1] "A" "B" "c" "D" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n" "o" "p" > "q" "r" "s" "t" "u" "v" "w" > [24] "x" "y" "z" "A" "B" "c" "D" "e" "f" "g" "h" "i" "j" "k" "l" "m" > "n" "o" "p" "q" "r" "s" "t" > [47] "u" "v" "w" "x" "y" "z" >> >
Based on this code I came up with the following function. replace2 <- function(x, ind, repl){ if(any(is.na(ind))) ind[is.na(ind)] <- 0 if(is.vector(x) & is.vector(repl)) { (x[ind != 0] <- repl[ind]) return(x) } else if(identical(ncol(x), ncol(repl))){ (x[ind != 0, ] <- repl[ind, ]) return(x) } } Whereas replicate() can be used only on vectors of same dimension, replicate2() can be used on vectors and matrices/dataframes, and the replacement data can have different nr of rows. It also works with index vectors containing NAs. > ##for vectors > (indx <- match(x, repl.tab[, 1], nomatch = 0)) [1] 2 3 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 [46] 0 0 0 0 0 0 0 > head(replace2(x, indx, repl.tab[, 2])) [1] "A" "B" "c" "D" "e" "f" > (indx <- match(x, repl.tab[, 1])) ##index vector with NAs [1] 2 3 NA 5 NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA 2 3 NA 5 [31] NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA > head(replace2(x, indx, repl.tab[, 2])) [1] "A" "B" "c" "D" "e" "f" > ##for matrices/dataframes > head(xx <- cbind(x, x)) x x [1,] "a" "a" [2,] "b" "b" [3,] "c" "c" [4,] "d" "d" [5,] "e" "e" [6,] "f" "f" > (repl.tab2 <- cbind(repl.tab[, 2], repl.tab[, 2])) [,1] [,2] [1,] "aa" "aa" [2,] "A" "A" [3,] "B" "B" [4,] NA NA [5,] "D" "D" [6,] "zz" "zz" > head(replace2(xx, indx, repl.tab2)) x x [1,] "A" "A" [2,] "B" "B" [3,] "c" "c" [4,] "D" "D" [5,] "e" "e" [6,] "f" "f" Does this function have any generic value? Are there obvious implementation mistakes? Regards Liviu ______________________________________________ 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.