python版本2.7.3导入maxrepeat modu时出现问题

Question

我正在尝试在python2.7.3中导入maxreat模块，但是在google中找不到太多的信息

帮助maxrepeat模块工作的模块是什么

我可以使用“from\u sre import maxreat”导入maxreat模块，但在运行nninv automation时仍然失败

Answer 1

MAXREPEAT由re模块内部使用，作为可以在模式中指定的最小、最大或确切重复次数的上限。例如：

>>> import re
>>> re.compile(r'a{100}')         # exactly 100 "a"s
<_sre.SRE_Pattern object at 0x7fa68be10780>
>>> re.compile(r'a{100, 200}')    # between 100 and 200 "a"s

在重复值中等于或超过MAXREPEAT会导致模块sre_parse中的正则表达式解析器引发异常：

>>> from sre_constants import MAXREPEAT
>>> MAXREPEAT
4294967295L

>>> re.compile(r'a{{{}}}'.format(MAXREPEAT-1))
<_sre.SRE_Pattern object at 0x7f0ec959f660>

>>> re.compile(r'a{{{}}}'.format(MAXREPEAT))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib64/python2.7/re.py", line 194, in compile
    return _compile(pattern, flags)
  File "/usr/lib64/python2.7/re.py", line 249, in _compile
    p = sre_compile.compile(pattern, flags)
  File "/usr/lib64/python2.7/sre_compile.py", line 572, in compile
    p = sre_parse.parse(p, flags)
  File "/usr/lib64/python2.7/sre_parse.py", line 716, in parse
    p = _parse_sub(source, pattern, 0)
  File "/usr/lib64/python2.7/sre_parse.py", line 324, in _parse_sub
    itemsappend(_parse(source, state))
  File "/usr/lib64/python2.7/sre_parse.py", line 518, in _parse
    raise OverflowError("the repetition number is too large")
OverflowError: the repetition number is too large

在正常使用re模块时，不应该有任何理由关心MAXREPEAT。如果需要处理错误，请使用异常：

try:
    re.compile(r'a{{{}}}'.format(MAXREPEAT))
except OverflowError as exc:
    print 'Failed to compile pattern: {}'.format(exc.message)