注意：Python2.x中正则表达式的最大匹配长度

fffonion

11 年前

Python 2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)]on win 32
Type "help", "copyright", "credits" or "license" for more information.
>>> import re
>>> a='1'*100000
>>> len(re.findall('\d+',a)[0])
65535

Python 2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)]on win 32

Type "help", "copyright", "credits" or "license" for more information.

>>> import re

>>> a='1'*100000

>>> len(re.findall('\d+',a)[0])

65535

简直sad

python3中这个bug被修正了 [141011]2.7.8中也已无此bug

Python 3.3.3 (v3.3.3:c3896275c0f6, Nov 18 2013, 21:18:40) [MSC v.1600 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import re
>>> a='1'*100000
>>> len(re.findall('\d+',a)[0])
100000

Python 3.3.3 (v3.3.3:c3896275c0f6, Nov 18 2013, 21:18:40) [MSC v.1600 32 bit (Intel)] on win32

Type "help", "copyright", "credits" or "license" for more information.

>>> import re

>>> a='1'*100000

>>> len(re.findall('\d+',a)[0])

100000

然后我看到了这里http://stackoverflow.com/questions/19773621/whats-the-maximum-number-of-repetitions-allowed-in-a-python-regex

然后尝试

Python 2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)]on win 32
>>> import sre_constants
>>> sre_constants.MAXREPEAT
65535

Python 2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)]on win 32

>>> import sre_constants

>>> sre_constants.MAXREPEAT

65535

以及

Python 3.3.3 (v3.3.3:c3896275c0f6, Nov 18 2013, 21:18:40) [MSC v.1600 32 bit (Intel)] on win32
>>> import sre_constants
>>> sre_constants.MAXREPEAT
2147483647

Python 3.3.3 (v3.3.3:c3896275c0f6, Nov 18 2013, 21:18:40) [MSC v.1600 32 bit (Intel)] on win32

>>> import sre_constants

>>> sre_constants.MAXREPEAT

2147483647

整(full)个(a)人(person)都(all)不(not)好(good)了(le)