Gabor Grothendieck <ggrothendieck <at> myway.com> writes:
>
> Liaw, Andy <andy_liaw <at> merck.com> writes:
> > Does anyone know how to test whether a
> > character can be coerced into numeric without generating a warning?
>
> res <- tryCatch(as.numeric(x), warning = function(x)x)
>
> res is now numeric if x was successfully converted and is unchanged
> if it was not. You can test res using is.numeric and take
> appropriate action or you can put the action into the body of the
> warning function such as having it return 0.
Sorry. The above has an error. It should be:
# res is x converted to numeric or x without change if that fails
res <- tryCatch(as.numeric(x), warning = function(warn)x)
or
# res is x converted to numeric or 0 if that fails
res <- tryCatch(as.numeric(x), warning = function(warn)0)
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