[Python-3000] range() issues

[Mark Dickinson]

On Tue, Apr 29, 2008 at 4:30 PM, Alexander Belopolsky <
alexander.belopolsky at gmail.com> wrote:

> I would say that if it is possible that n exceeds a few hundred
> million, it is a good idea to pause and think whether you want to have
> this loop implemented in Python to begin with.
>

Maybe.  But the answer is often going to be yes, if it's a choice between
me spending some number of hours translating everything to C, or just
leaving my computer do the work (however inefficiently) while I do
something else.

These numbers aren't ridiculously large.  I just tried

for i in range(2**31): pass

on my (32-bit) laptop: it took 736.8 seconds, or about 12 and a bit minutes.
(An aside: in contrast,

for i in range(2**31-1): pass

took only 131.1 seconds;  looks like there's some potential for optimization
here....)

Put another way:  range(n) currently works, in Py3k, for n > sys.maxsize.
What's the rationale for breaking that?

extention (combined with a 64-bit OS) may be a good idea if you
> routinely iterate over huge datasets.
>

Well, huge datasets (large time *and* space requirements) don't really
come into it for my typical use-cases:  just long-running processes.

Mark
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