Message245184
Here is a patch that adds more optimizations for searching patterns that starts with a literal string and groups. In particular it includes a case when a pattern starts with a group containing single character.
Examples:
$ ./python -m timeit -s "import re; p = re.compile('(\n)'); s = ('a'*100 + '\n')*1000" -- "p.split(s)"
Unpatched: 100 loops, best of 3: 4.58 msec per loop
Patched : 1000 loops, best of 3: 562 usec per loop
$ ./python -m timeit -s "import re; p = re.compile('(\n\r)'); s = ('a'*100 + '\n\r')*1000" -- "p.split(s)"
Unpatched: 100 loops, best of 3: 3.1 msec per loop
Patched : 1000 loops, best of 3: 663 usec per loop
For comparison:
$ ./python -m timeit -s "import re; p = re.compile('\n'); s = ('a'*100 + '\n')*1000" -- "p.split(s)"
1000 loops, best of 3: 329 usec per loop
$ ./python -m timeit -s "import re; p = re.compile('\n\r'); s = ('a'*100 + '\n\r')*1000" -- "p.split(s)"
1000 loops, best of 3: 338 usec per loop
Optimized also more complex but rare cases, such as '\n()\r' or '((\n)(\r))'.
Fast searching no longer can be disabled. |
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Date |
User |
Action |
Args |
2015-06-11 20:22:51 | serhiy.storchaka | set | recipients:
+ serhiy.storchaka, ezio.melotti, mrabarnett, Patrick Maupin |
2015-06-11 20:22:51 | serhiy.storchaka | set | messageid: <1434054171.6.0.295017496904.issue24426@psf.upfronthosting.co.za> |
2015-06-11 20:22:51 | serhiy.storchaka | link | issue24426 messages |
2015-06-11 20:22:51 | serhiy.storchaka | create | |
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