[R] Assigning line colors in xyplot

[hadley wickham]

On 8/31/07, Christof Bigler <christof.bigler at env.ethz.ch> wrote:
> The suggestions by Deepayan Sarkar and Hadley Wickham work for that
> case, but I get into troubles when I try to draw e.g. a panel for "A"
> and "B":
>
> xyplot(y ~ x | f , groups=g, data=tmp,type="l",
>       par.settings=list(superpose.line=list(col=c("red","blue"))),
>       auto.key=list(space="top",
> text=levels(tmp$f),points=FALSE,lines=TRUE))

In ggplot, you would need to specify the grouping variable as well as
the colour variable:

qplot(x, y, data=tmp, geom="line", colour=f, group=interaction(f,g))

which should work for any facetting.

Hadley