[Rd] points(*, pch=NA) does *not* not draw the point (PR#6876)
ripley at stats.ox.ac.uk
ripley at stats.ox.ac.uk
Wed May 12 16:45:49 CEST 2004
On Wed, 12 May 2004, Martin Maechler wrote:
> >>>>> "BDR" == Prof Brian Ripley <ripley at stats.ox.ac.uk>
> >>>>> on Wed, 12 May 2004 15:20:56 +0100 (BST) writes:
>
> BDR> On Wed, 12 May 2004 maechler at stat.math.ethz.ch wrote:
> >> We say in ?points that 'pch' (among others) can be set to
> >> NA for omitting a point.
>
> BDR> I don't think we actually do. We say
>
> BDR> Points whose 'x', 'y', 'pch', 'col' or 'cex' value
> BDR> is 'NA' are omitted from the plot.
>
> BDR> and earlier
>
> BDR> either be a 'character' or an integer code
>
> BDR> I read that to mean that as.logical(NA) is incorrect,
> BDR> but that as.character(NA) is correct and should result
> BDR> in the point being omitted.
>
> BDR> In short, I disagree as to which is a very strict bug
> BDR> (although it makes sense to allow logical NAs, of
> BDR> course).
>
> You're right, with both statements.
>
> BDR> The problems are both in FixupPch in src/main/plot.c.
> BDR> Can I leave you to fix both?
>
> yes, I've been in there anyway.
>
> There's one remaining design decision:
>
> At the moment I'd go to allow 'logical' and coerce that to
> integer (as in many other S code places).
> Alternatively, more strict behavior would only allow NA logicals
> and give an error for TRUE or FALSE entries in pch vectors.
> I currently think it's not worth the extra check.
Here it probably makes more sense to coerce to character, and given the
ambiguity I would allow only an all-NA logical vector.
Brian
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
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