(python语言)为什么正则表达式的 贪婪匹配模式 比 非贪婪模式 得到的匹配结果还要短？ Python 正则表达式 非贪婪匹配问题
python \u6b63\u5219\u8868\u8fbe\u5f0f \u975e\u8d2a\u5a6a\u5339\u914d\u95ee\u9898tim@tim-1215B:~$ python
Python 2.7.2+ (default, Oct 4 2011, 20:06:09)
[GCC 4.6.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import re
>>> data = 'Thu Feb 15 17:46:04 2007::[email protected]:: 2341123-6-8'
>>> patt = re.compile(r'.+(\d+-\d-\d)', re.X)
>>> print patt.match(data).group(1)
3-6-8
>>> patt = re.compile(r'.+?(\d+-\d-\d)', re.X)
>>> print patt.match(data).group(1)
2341123-6-8
>>>
\u7b2c\u4e8c\u6355\u83b7\u62ec\u53f7\u91cc\u9762\u662f (0*) \u2014\u20140\u4e2a\u6216\u591a\u4e2a0\uff0c \u540e\u9762\u63a5\u7740\u662f$\u2014\u2014\u884c\u5c3e,
02300\u2014\u2014\u4e0d\u6ee1\u8db3\u591a\u4e2a0.
\u6b63\u5219\u8868\u8fbe\u5f0f\u6539\u4e3a\uff1a
^(\d+?)(0.*)$
\u7ed3\u679c\u5c31\u4f1a\u662f\uff1a
("1", "02300")
不清楚你的贪婪模式的正则是怎么的：.*(a.*?a).* or .*?(a.*a).* or .*(a.*a).*
你给的例子匹配并没有问题
.*? 匹配的空
a.*?a 匹配的aqwertya
.* 匹配的aple
你可以试试给每段正则都加个分组然后打印每个分组的匹配结果，然后修改正则为贪婪和非贪婪分别看看结果。这样有助于你理解学习。
str='aqwertyaaple'
regex_str='(.*?)(a.*?a)(.*)'
match_obj=re.match(regex_str,str)
match_obj.group(1)
match_obj.group(2)
match_obj.group(3)
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