[Rd] Small change to plot.xy

[ripley@stats.ox.ac.uk]

On Sat, 23 Nov 2002, Jonathan Rougier wrote:

> ripley@stats.ox.ac.uk wrote:
>
> > > I can see that both of these have merit, but I think they are both easy
> > > to work around, if necessary.  No-one has disagreed that it's natural to
> > > want to pass a factor to col, and I believe that the vast majority of
> > > times when this occurs the factor is not designed explicitly to paint
> > > the points.
> >
> > I did disagree.  I don't see why users should not explicitly map the
> > factor levels to colours, which takes only a few extra characters.
> > People have been doing this for a decade in S without objecting.
> > Why is it worth complicating R for?
>
> That's the difference between us: you think they should have to type a
> few extra characters to achieve a natural result, and I don't.  It's two
> extra lines in the source and an extra line in the help file -- I don't
> call this a complication and I think that the next generation of
> statisticians will be that much more taken with R (as opposed to, say,
> SPSS) if we take the trouble to make the default behaviour as intuitive
> as possible.

No, the difference is that what you find `intuitive' other people find
perverse.  Giving a factor of colour names and getting a different set of
colours is perverse.  If the intention is not clear, it is more
`intuitive' to give an error than to guess incorrectly.

Does SPSS actually do this, that is arbitrarily assign colours to
categories that might be names of colours?

-- 
Brian D. Ripley,                  ripley@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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595