Python 无法编译正则表达式

Question

我正在尝试使用 python 正则表达式从 cmake 文件中检测所有 set，如下文件:

# Library to include
set(LIB_TO_INCLUDE 
        a
        b
        c)

# comon code (inclusion in source code)
set(SHARED_TO_INCLUDE d e f)

# Library to include
set(THIRD_PARTY g h)

我想检索:

LIB_TO_INCLUDE a b c
SHARED_TO_INCLUDE d e f
THIRD_PARTY g h

我测试了正则表达式 set\((?s:[^)])*?\) (获取除 ) 后面的所有项目 set()使用 regex101.com (参见 https://regex101.com/r/aB5tX2/1 )，它显然做了我想要的。

现在，当我尝试从 Python 运行 re.compile(r'set\((?s:[^)])*?\)') 时，出现错误:

  File "private\python_scripts\convert.py", line 34, in create_sde_files
    pattern = re.compile(r'set\((?s:[^)])*?\)')   File "b:\dev\vobs_ext_2015\tools_ext\python\Python34_light\lib\re.py", line 223, in compile
    return _compile(pattern, flags)   File "b:\dev\vobs_ext_2015\tools_ext\python\Python34_light\lib\re.py", line 294, in _compile
    p = sre_compile.compile(pattern, flags)   File "b:\dev\vobs_ext_2015\tools_ext\python\Python34_light\lib\sre_compile.py", line 568, in compile
    p = sre_parse.parse(p, flags)   File "b:\dev\vobs_ext_2015\tools_ext\python\Python34_light\lib\sre_parse.py", line 760, in parse
    p = _parse_sub(source, pattern, 0)   File "b:\dev\vobs_ext_2015\tools_ext\python\Python34_light\lib\sre_parse.py", line 370, in _parse_sub
    itemsappend(_parse(source, state))   File "b:\dev\vobs_ext_2015\tools_ext\python\Python34_light\lib\sre_parse.py", line 721, in _parse
    raise error("unknown extension") sre_constants.error: unknown extension

Python不支持这种正则表达式吗？

Answer 1

这应该可以做到:set\(([^)]*?)\)

编译正则表达式时，“单行”修饰符将作为参数传递:

>>> t = """set(LIB_TO_INCLUDE 
...         a
...         b
...         c)"""
>>> 
>>> pattern = r'set\(([^)]*?)\)'
>>> 
>>> regex = re.compile(pattern, re.S)
>>> 
>>> result = regex.search(t).groups()[0]
>>> result
'LIB_TO_INCLUDE \n        a\n        b\n        c'

然后您可以消除额外的间距和新行:

>>> ' '.join(x.strip() for x in result.split('\n'))
'LIB_TO_INCLUDE a b c'

请注意，在您的链接中，如果您在左侧的“ flavor ”中切换到“python”，您将收到特定格式导致的错误。

编辑:要获取所有 (3) 个匹配项，您需要使用 <regex>.findall(...)而不是search .

>>> tt = """# Library to include
... set(LIB_TO_INCLUDE 
...         a
...         b
...         c)
... 
... # comon code (inclusion in source code)
... set(SHARED_TO_INCLUDE d e f)
... 
... # Library to include
... set(THIRD_PARTY g h)"""
>>> 

>>> result = regex.findall(tt)
>>> result
['LIB_TO_INCLUDE \n        a\n        b\n        c', 'SHARED_TO_INCLUDE d e f', 'THIRD_PARTY g h']