在Python中，我可以使用re.compile将正则表达式编译为不区分大小写:
>>> s = 'TeSt'
>>> casesensitive = re.compile('test')
>>> ignorecase = re.compile('test', re.IGNORECASE)
>>>
>>> print casesensitive.match(s)
None
>>> print ignorecase.match(s)
<_sre.SRE_Match object at 0x02F0B608>
是否有一种方法可以做同样的事情，但不使用re.compile。我在文档中找不到任何类似Perl的I后缀(例如m/test/ I)的东西。
当前回答
#'re.IGNORECASE' for case insensitive results short form re.I
#'re.match' returns the first match located from the start of the string.
#'re.search' returns location of the where the match is found
#'re.compile' creates a regex object that can be used for multiple matches
>>> s = r'TeSt'
>>> print (re.match(s, r'test123', re.I))
<_sre.SRE_Match object; span=(0, 4), match='test'>
# OR
>>> pattern = re.compile(s, re.I)
>>> print(pattern.match(r'test123'))
<_sre.SRE_Match object; span=(0, 4), match='test'>
其他回答
将re.IGNORECASE传递给search、match或sub的flags参数:
re.search('test', 'TeSt', re.IGNORECASE)
re.match('test', 'TeSt', re.IGNORECASE)
re.sub('test', 'xxxx', 'Testing', flags=re.IGNORECASE)
你也可以使用不带IGNORECASE标志的搜索/匹配执行不区分大小写的搜索(在Python 2.7.3中测试):
re.search(r'(?i)test', 'TeSt').group() ## returns 'TeSt'
re.match(r'(?i)test', 'TeSt').group() ## returns 'TeSt'
进口
import re
在运行时处理中:
RE_TEST = r'test'
if re.match(RE_TEST, 'TeSt', re.IGNORECASE):
应该提到的是，不使用re.compile是一种浪费。每次调用上述匹配方法时，正则表达式都将被编译。这在其他编程语言中也是错误的做法。下面是更好的实践。
在应用程序初始化中:
self.RE_TEST = re.compile('test', re.IGNORECASE)
在运行时处理中:
if self.RE_TEST.match('TeSt'):
如果你想替换但仍然保持前str的风格，这是可能的。
例如:突出显示字符串“test asdasd test asd test asdasd”。
sentence = "test asdasd TEST asd tEst asdasd"
result = re.sub(
'(test)',
r'<b>\1</b>', # \1 here indicates first matching group.
sentence,
flags=re.IGNORECASE)
test asdasd测试asdasd
#'re.IGNORECASE' for case insensitive results short form re.I
#'re.match' returns the first match located from the start of the string.
#'re.search' returns location of the where the match is found
#'re.compile' creates a regex object that can be used for multiple matches
>>> s = r'TeSt'
>>> print (re.match(s, r'test123', re.I))
<_sre.SRE_Match object; span=(0, 4), match='test'>
# OR
>>> pattern = re.compile(s, re.I)
>>> print(pattern.match(r'test123'))
<_sre.SRE_Match object; span=(0, 4), match='test'>
