avoiding too many loops - reshaping data

Beware of facile comparisons of this sort -- they may be apples and nematodes.

And they also imply that the main time sink is the computation.  In my
experience, figuring out how to solve the problem using takes
considerably more time than 18 / 1000 seconds, and so investing your
energy in learning idioms that apply in a wide range of situations is
far more useful than figuring out the fastest solution to a single
problem.

Hadley

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