Ranking within a classification variable.

Here's one way:

<snip>

dat$rank <- with(dat, ave(x, f, FUN=rank))

<snip>

Don't know how this rates on the slick-quick-sexy scale...

Thanks Andy.  That's definitely a 10 on the slick-quick-sexy scale.
I (blush!) didn't know about ``ave()''.

			cheers,

				Rolf