NEWBIE: ishexdigit revisited

Paul Rubin http
Tue Dec 30 22:45:13 CET 2003


Kirk Strauser <kirk at strauser.com> writes:
> >>> def retest():
> ...     for i in xrange(1000000):
> ...             re.match(r'unlikely.*pat(..(.))?tern$', 'test')
> ...
> >>> def retest2():
> ...     pat = re.compile(r'unlikely.*pat(..(.))?tern$')
> ...     for i in xrange(1000000):
> ...             pat.match('test')
> ...
> >>> start = time.time(); retest(); stop = time.time(); print stop - start
> 5.28148591518
> >>> start = time.time(); retest2(); stop = time.time(); print stop - start
> 1.04278099537
> 
> Pre-compiling the pattern is a huge win on my system.

You're using an extreme example and seeing the cost of the cache
lookup in the first example.  You're certainly not seeing the pattern
get recompiled a million times in 5 seconds.  Doing would be many
times slower.




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