Empty Data Frame

Hi:

You could try something like

df <- data.frame( expand.grid( Week = 1:52, Year = 2002:2011 ))

expand.grid already returns a data frame...  You might want
KEEP.OUT.ATTRS = F though.  Even it feels like you are yelling at R.

Hadley

Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/