[R] panel.groups: use group.number to define colors

[baptiste auguie]

Dear list,


I've been trying this for a few hours and I just don't understand how  
lattice works with groups and subscripts.

Consider the following example,



> xx <- seq(1, 10, length=100)
> x <- rep(xx, 4)
> y <- c(cos(xx), sin(xx), xx, xx^2/10)
> fact <- factor(rep(c("cos", "sin", "id", "square"), each=100))
> fact2 <- factor(rep(c("periodic", "not periodic"), each=100))
>
> my.df <- data.frame(x=x, y=y, fact = fact, fact2 = fact2)
>
> head(my.df)
>
>
> myColors <- c(2, 4)
>
> 	xyplot(y ~ x | fact,  data = my.df, groups = fact2,
> 	      panel =  panel.superpose,
> 	      panel.groups = function(..., group.number) {
>
> 	         panel.xyplot(...)
> 			#panel.xyplot( ..., col=myColors[group.number]) # error
> 	
> 	      })


My aim is to assign a custom color to each group, but for some reason  
the col parameter is already given to panel.xyplot and I can't find  
where it gets the values from.

Many thanks,

baptiste

_____________________________

Baptiste Auguié

School of Physics
University of Exeter
Stocker Road,
Exeter, Devon,
EX4 4QL, UK

Phone: +44 1392 264187

http://newton.ex.ac.uk/research/emag