[Rd] R 2.8.0 qqnorm produces error with object of class zoo?

[Gabor Grothendieck]

On Wed, Oct 22, 2008 at 8:49 AM, Peter Dalgaard
<P.Dalgaard at biostat.ku.dk> wrote:
> Pfaff, Bernhard Dr. wrote:
>> It seems, that in my previous emails the attached output files got deleted, hence these are now copied below:
>>
>>
> (If the MIME type is wrong, then that will happen.)
>
> Anyways, the root cause seems to be the new function .gt() which is
> related to
>
>    o   New generic function xtfrm() as an auxiliary helper for
>        sort(), order() and rank().  This should return a numeric
>        vector that sorts in the same way as its input.  The default
>        method supports any class with ==, > and is.na() methods but
>        specific methods can be much faster.
>
>        As a side-effect, rank() will now work better on classed
>        objects, although possibly rather slowly.
>
> Here, "better" may be in the eyes of the beholder, for
>
>> dax[3]==dax[6]
> Data:
> logical(0)
>
> Index:
> integer(0)
>
> and accordingly
>
>> rank(dax)
> Error in if (xi == xj) 0L else if (xi > xj) 1L else -1L :
>  argument is of length zero
>
> which is the error that you are seeing.
>
> What to do about it is a bit dubious. Obviously, we don't want to "fix"
> .gt() so that it automatically unclasses objects, and I assume that zoo
> has its reasons for not wanting to compare series with different
> indices. So I suppose that either the user must unclass, or zoo define
> rank.zoo.

Actually qqnorm does not use rank but it does use order and with the
xtfrm.zoo method I mentioned qqnorm works with zoo; however, I think
rank needs to be fixed in R to make use of xtfrm as well since I would have
expected that supplying an xtfrm method for zoo would be sufficient to
get both order and rank to work without giving errors.  Also note that rank
is not generic.