[R] Sort a data frame

[Gabor Grothendieck]

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)