converting stata's by syntax to R

Chris Wallace <c.wallace at qmul.ac.uk> writes:

I am struggling with migrating some stata code to R....

Thanks to all who replied.  It was very helpful to see a combination
of more direct stata->R translations and more R-ish code.  which.max()
solves my problem this time, but learning about split(), unsplit() and
duplicated() should make such problems fewer in the long run.

C.