What you want is ConvertMissingToNA <- function (values) { values[ values == -9999 | values == -999999] <- NA return( values ) }
To see why your version doesn't do what you wanted, maybe it helps to consider the following? x <- 1:10 y <- (x[3:6] <- 99) y ## 99 (It's perhaps not entirely obvious that the value of y should be 99 and not c(99,99,99,99), but anyway, neither correspond to what you wanted.) Dan On Tue, Sep 16, 2008 at 03:19:53PM -0700, Hutchinson,David [PYR] wrote: > Hi R-Users, > > I wrote a simple function to change values of a matrix or vector to NA > based on the element value being -9999 or -999999. I don't understand > why the function returns a unit vector (NA) instead of setting all > values in the vector which have -9999 or -999999 to NA. When I apply the > function in line, it appears to work correctly? > > Can someone enlighten me what I am doing wrong? > > Thanks in advance. > > David > > > Here's my example: > > > ConvertMissingToNA <- function (values) { > return ( values[ values == -9999 | values == -999999] <- NA ) > } > > d <- floor(runif(10, 1, 100)) > pos <- floor (runif(5, 1, 10)) > d[pos] <- -9999 > pos <- floor (runif(2, 1, 10)) > d[pos] <- -999999 > print (d) > > # now apply function > e <- ConvertMissingToNA (d) # will return NA as a unit vector > print (e) > > # conduct function in-line > d[ d == -9999 | d == -999999] <- NA # correctly converts values to NA > print (d) > > ______________________________________________ > 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. -- http://www.stats.ox.ac.uk/~davison ______________________________________________ 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.