[R] coloring individual points in lattice xyplot

[Deepayan Sarkar]

On 7/4/06, Gabor Grothendieck <ggrothendieck at gmail.com> wrote:
> If I wish to color groups in xyplot I can do this:
>
>    library(lattice)
>    x <- 1:10
>    y <- cbind(x, x+1)
>    xyplot(y ~ rep(x,2), group = col(y), col = 1:2)
>
> How do I color different points differently within a group.
>
> For example, I want to produce this plot (except that I only
> want to have two groups, not 11):
>
>    xyplot(y ~ rep(x,2), group = c(rep(1, 10), 2:11), col = 1:11)
>
> I am thinking of something like this (although
> this does not work, its just to get the idea across):
>
>    xyplot(y ~ rep(x,2), group = col(y), col = list(1, 2:11))
>
> where, in general, I have a list with one component per group
> whose elements are scalars to color the whole group or
> vectors one color per point in the group.  I don't know
> ahead of time what the list is.
>
> I am looking for a general approach to this within the lattice
> xyplot plot framework; the above is just an example.

The general approach is to write your own panel function. For a
possible template, look at the functions panel.superpose and
panel.superpose.2 and how they handle the 'type' argument.

Deepayan