R help - May 2007 - Separate x-axis ticks for panels in xyplot()?

Dear r-helpers,

In an xyplot I have

xyplot(y ~ x | c, groups = g,
	scales = list(
		x = list(
			at = v1,
			labels = c('A', 'B', 'C', 'D'),
			rot = 45
		)
	)
)

g consists of two groups. How do I define a different set of x ticks  
and labels for the second panel? I'm looking for something like

xyplot(y ~ x | c, groups = g,
	scales = list(
		x = list(ifelse(g == g1, {
			at = v1,
			labels = c('A', 'B', 'C', 'D'),
			rot = 45},
			{at = v2,
			labels = c('E', 'F' 'G"),
			rot = 45}
		)
	)
)


_____________________________
Professor Michael Kubovy
University of Virginia
Department of Psychology
USPS:     P.O.Box 400400    Charlottesville, VA 22904-4400
Parcels:    Room 102        Gilmer Hall
         McCormick Road    Charlottesville, VA 22903
Office:    B011    +1-434-982-4729
Lab:        B019    +1-434-982-4751
Fax:        +1-434-982-4766
WWW:    http://www.people.virginia.edu/~mk9y/

This will get you started.

Rich




tmp <- data.frame(y=rnorm(20), x=rnorm(20),
                  c=factor(rep(letters[1:5], 4)),
                  g=factor(rep(1:2, each=10)))
v1 <- seq(-1.5, 0, .5)
v2 <- 0:2


xyplot(y ~ x | c, groups = g, data=tmp,
       scales = list(x = list(
                       relation="sliced",
                       at = rep(list(v1, v2), length=5),
                       labels = rep(list(
                         c('A', 'B', 'C', 'D'),
                         c('E', 'F', 'G')), length=5),
                       rot = 45)))