R help - Oct 2003 - auto.key = TRUE in xyplot() draws max. 7 groups

In the example below:

library(lattice)
n = 100
a = rnorm(n)
b = rnorm(n)
c = sample(c(1:7), n, repl=TRUE)
xyplot(a ~ b, groups = c, auto.key = TRUE)
c = sample(c(1:8), n, repl=TRUE)
xyplot(a ~ b, groups = c, auto.key = TRUE)

a key is drawn for the first, but not for the
second graph. I suppose it has to do with the
number of groups. If not a bug, maybe
this should go into the documentation?
--
Edzer

On Monday 06 October 2003 03:19, Edzer J. Pebesma wrote:
> In the example below:
>
> library(lattice)
> n = 100
> a = rnorm(n)
> b = rnorm(n)
> c = sample(c(1:7), n, repl=TRUE)
> xyplot(a ~ b, groups = c, auto.key = TRUE)
> c = sample(c(1:8), n, repl=TRUE)
> xyplot(a ~ b, groups = c, auto.key = TRUE)
>
> a key is drawn for the first, but not for the
> second graph. I suppose it has to do with the
> number of groups. If not a bug, maybe
> this should go into the documentation?
Definitely a bug (in Rows). If you are using R 1.7.1, redefining Rows as 
follows should fix the problem.

Rows <- function (x, which) 
{
    for (i in seq(along = x)) x[[i]] <- 
        rep(x[[i]], length = max(which, length(which)))[which]
    x
}

Deepayan