[R] dotplot (lattice) with panel.segments and groups

[Gabor Grothendieck]

On 7/7/06, Deepayan Sarkar <deepayan.sarkar at gmail.com> wrote:
> On 7/7/06, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> > Could you explain what panel.groups= does and what the difference
> > is between panel.groups= and panel= ?  In ?xyplot it just says:
> >
> > panel.groups: useful mostly for 'xyplot' and 'densityplot'. Applies
> >           when 'panel' is 'panel.superpose' (which happens by default
> >           in these cases if 'groups' is non-null)
> >
> > which indicates when it might apply but not what it does.
>
> That's wrong (it used to be right - a good example of why \synopsis is
> bad). Since lattice 0.13-x, panel.superpose is never the default panel
> function. An updated version with improved documentation should be out
> soon.
>
> 'panel.groups' is simply an argument to panel.superpose, and is
> described in ?panel.superpose. Thus, it only makes sense as an
> argument to xyplot/dotplot/whatever when the panel function is
> panel.superpose, and not otherwise. The entry for the graphical
> parameters in ?panel.superpose isn't as useful as it could be, I have
> just updated it to read:
>
> col, col.line, col.symbol, pch, cex, fill, font, fontface,
> fontfamily, lty, lwd, alpha: graphical
>          parameters, replicated to be as long as the number of
>          groups.  These are eventually passed down to 'panel.groups',
>          but as scalars rather than vectors.  When 'panel.groups' is
>          called for the i-th level of 'groups', the corresponding
>          element of each graphical parameter is passed to it.
>
> Hope that makes things a bit clearer.
>
> Deepayan
>

Thanks.  That does help.