Thanks for that. I am having some difficulty figuring out how it
works. The help page tells me (I think) that "y<-log(x)" gets matched
to expr. Am I correct in thinking that if either an error or warning
is produced, that tryCatch silently returns <something> (or
<nothing>?) to the for loop, and only otherwise goes on to evaluate
the rest of the second assignment and break call? So any warning would
abort processing of the remaining expressions?
Are the assignment "xx<-x" and the break call considered "handlers" as
described in the help page?
I see the purpose of the last argument. Taking out the warning =
function(w{}) changes the behavior when none of the elements in the
vector passed to x were valid.
> for (x in c(-2, -1)) {
+ tryCatch({
+ y <- log(x)
+ xx <- x
+ break
+ })
+ }
Warning message:
In log(x) : NaNs produced
> print(xx)
[1] -2
--
David Winsemius
On Dec 7, 2008, at 12:21 PM, Gabor Grothendieck wrote:
Try this:
for (x in c(-2, 2, 4)) {
tryCatch({
y <- log(x)
xx <- x
break
}, warning = function(w) {})
}
print(xx) # 2
On Sun, Dec 7, 2008 at 2:38 AM, Andreas Wittmann
<[EMAIL PROTECTED]> wrote:
Dear R useRs,
with the following piece of code i try to find the first value
which can be
calculated without warnings
`test` <- function(a)
{
repeat
{
## hide warnings
suppressWarnings(log(a))
if (exists("last.warning", envir = .GlobalEnv))
{
a <- a + 0.1
## clear existing warnings
rm("last.warning", envir = .GlobalEnv)
}
if(a > 5 || !exists("last.warning", envir = .GlobalEnv))
break
}
return(a)
}
if i run this with test(-3), i would expect a=0 as return value.
Is it also possible to hide warnings during my function, i guess i
use
suppressWarnings in a wrong way here?
Thanks and best regards
Andreas
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and provide commented, minimal, self-contained, reproducible code.
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
