[R] stopifnot with logical(0)

William Dunlap wdunlap at tibco.com
Fri Dec 11 15:55:52 CET 2015


The reason is probably that
   any(logical())
and
   any(!logical())
return FALSE (there are no TRUEs in logical(0)).
Bill Dunlap
TIBCO Software
wdunlap tibco.com


On Fri, Dec 11, 2015 at 5:38 AM, Dario Beraldi <dario.beraldi at gmail.com> wrote:
> Hi All,
>
> I'd like to understand the reason why stopifnot(logical(0) == x) doesn't
> (never?) throw an exception, at least in these cases:
>
> stopifnot(logical(0) == 1)
> stopifnot(logical(0) == TRUE)
> stopifnot(logical(0) == FALSE)
>
> My understanding is that logical(0) is an empty set, so I would expect the
> above tests to fail.
>
> (I got bitten by this in a piece of code where "x" happened to be
> logical(0) and stopifnot didn't catch it)
>
> Thanks!
> Dario
>
>         [[alternative HTML version deleted]]
>
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