问题
So I'm doing a little bit of testing for something and I require a method of splitting a string into groups of two. (e.g. 'abcdef' => ['ab','cd','ef'])
I'm trying to use a regex pattern to do this ([^]{2}). Whenever I try to compile this pattern, I get the error message:
sre_constants.error: unexpected end of regular expression
The exact line of code is:pat = re.compile(r'[^]{2}')
Could someone please tell me what I'm doing wrong here? I've done a lot of searching but a lot of the problems were related to incorrect usage and/or backslashes.
I thought about it possibly being because of string formatting, though the Python docs didn't mention anything about any issues.
回答1:
Use
(.{2})
Dot will match any character. If you want to match newline characters with dot do not forget to add s modifier. So your code will look like this
p = re.compile('(?s)(.{2})')
Also I am not sure why you want to use regular expressions for the task. You can do it with following snippet
In [5]: line = 'abcdef'
In [6]: n = 2
In [7]: [line[i:i+n] for i in xrange(0, len(line), n)]
Out[7]: ['ab', 'cd', 'ef']
回答2:
It is true that in JavaScript [^] means "match any character" (though even regex101 says: "Note: Avoid this construct, use . or [\s\S] instead."). However, in Python, [^] is an invalid character class (see this example on regex101).
Use (?s)(.{2}).
See demo.
(?s) inline option will make sure you also match the newline characters.
来源：https://stackoverflow.com/questions/29917384/sre-constants-error-unexpected-end-of-regular-expression-should-work-fine