[Python-3000] optimizing [x]range

Tue Jul 31 03:18:41 CEST 2007

skip at pobox.com wrote:
> Given that I find the cascading comparisons clearer I see no reason
> to optimize the "in range(...)" case.

The sort of thing I have in mind is where I have a sequence
that I want to frequently iterate over the indices of, so
I do
 r = xrange(len(myseq))
so I can write
 for i in r:
 ...
Having done that, if I want to test whether some index j
is within the range of indices for this sequence, it
seems natural to write
 if j in r:
 ...
Given the context, I think this is a very Obvious Way To
Do It, and it's surprising that it isn't as efficient as it
looks like it should be.
--
Greg