[R] drop.unused.levels for two factors {lattice}

[Dylan Beaudette]

Hi,

Is there any way to suppress plotting of panels that don't actually contain 
any information? I have tried using 'drop.unused.levels=TRUE', but there 
doesn't seem to be any effect. Here is an example:

library(lattice)

# some fake data:
d <- data.frame(x=runif(20), x.class=rep(letters[1:5], each=4),  
f1=rep(letters[1:2], each=10), f2=rep(letters[10:19], each=2) )

# plot it:
dotplot(x.class ~ x | f1 + f2, data=d, scales=list(relation='free'))

Thanks,

Dylan

-- 
Dylan Beaudette
Soil Resource Laboratory
http://casoilresource.lawr.ucdavis.edu/
University of California at Davis
530.754.7341