psss...I want to move from Perl to Python
MRAB
python at mrabarnett.plus.com
Sat Jan 30 22:43:48 EST 2016
On 2016-01-31 01:56:51, "Steven D'Aprano"
<steve+comp.lang.python at pearwood.info> wrote:
>On Sunday 31 January 2016 09:18, Gregory Ewing wrote:
>
>> Rustom Mody wrote:
>>> 1. One can use string-re's instead of compiled re's
>>
>> And I gather that string REs are compiled on first use and
>> cached, so you don't lose much by using them most of the
>> time.
>
>Correct. The re module keeps a cache of the last N regexes used, for
>some
>value of N (possibly 10?) so for casual use there's no real point to
>pre-
>compiling other than fussiness.
>
In Python 3.5, it's 512.
>
>But if you have an application that makes heavy-duty use of regexes,
>e.g.
>some sort of parser with dozens of distinct regexes, you might not want
>to
>rely on the cache.
>
It's slightly faster to use a pre-compiled regex because it won't have
to look it up in the cache, although most of the time it probably won't
matter.
More information about the Python-list
mailing list