如何在python3中将复杂的正则表达式写为字符串？

Question

So, I've got this regex I would like to compile:

(?<!\\)(?:(')|")(?(1)(\\'|[^'\r])+?'|(\\"|[^\r"])+?")

It works fine. But because there are ' and " signs, I need to escape them. So I do:

re.compile('''(?<!\\)(?:(')|")(?(1)(\\'|[^'\r])+?'|(\\"|[^\r"])+?")''')

Which give me the 'unbalanced parenthesis' error. I also tried:

re.compile('(?<!\\)(?:(\')|")(?(1)(\\\'|[^\'\r])+?\'|(\\"|[^\r"])+?")')

Are all those backslashes confusing it, somehow? It's hard enough to understand without having to add more backslashes to escape the backslashes...

Answer 1

Yes, they are. Use a raw string.

>>> re.compile(r'(?<!\\)(?:(\')|")(?(1)(\\\'|[^\'\r])+?\'|(\\"|[^\r"])+?")')
<_sre.SRE_Pattern object at 0x242aa60>