[R] Unexpected returned value from a function

[jim holtman]

try this -- you have to return the entire vector:

ConvertMissingToNA <- function (values) {
 values[ values == -9999 | values == -999999] <- NA
 values
}

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)

On Tue, Sep 16, 2008 at 6:19 PM, Hutchinson,David [PYR]
<David.Hutchinson at ec.gc.ca> 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)
>
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>



-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?