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
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)
其他回答
不区分大小写的标记(?i)可以直接合并到正则表达式模式中:
>>> import re
>>> s = 'This is one Test, another TEST, and another test.'
>>> re.findall('(?i)test', s)
['Test', 'TEST', 'test']
要执行不区分大小写的操作，请提供re.IGNORECASE
>>> import re
>>> test = 'UPPER TEXT, lower text, Mixed Text'
>>> re.findall('text', test, flags=re.IGNORECASE)
['TEXT', 'text', 'Text']
如果我们想替换匹配大小写的文本…
>>> def matchcase(word):
def replace(m):
text = m.group()
if text.isupper():
return word.upper()
elif text.islower():
return word.lower()
elif text[0].isupper():
return word.capitalize()
else:
return word
return replace
>>> re.sub('text', matchcase('word'), test, flags=re.IGNORECASE)
'UPPER WORD, lower word, Mixed Word'
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)
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'>
