问题
I have two regular expressions, for use with Regex.Split:
(?<=\G[^,],[^,],)
and
(?<=\G([^,],){2})
When splitting the string "A,B,C,D,E,F,G,", the first one results in:
A,B,
C,D,
E,F,
G,
and the second results in:
A,B,
A,
C,D,
C,
E,F,
E,
G,
What is going on here? I thought that (X){2} was always equivalent to XX, but I'm not sure anymore. In my actual problem, I need to do something like quite a bit more complex, and I need to do it sixty nine times, so just repeating the pattern is less than ideal.
回答1:
From the documentation for Regex.Split
If capturing parentheses are used in a Regex.Split expression, any captured text is included in the resulting string array.
The internal parentheses are capturing. Try using (?:[^,],) instead.
回答2:
From docs:
If capturing parentheses are used in a Regex.Split expression, any captured text is included in the resulting string array.
You have a capture group in your second expression. Try non-capturing parens:
(?<=\G(?:[^,],){2})
来源：https://stackoverflow.com/questions/19286238/is-this-a-bug-in-nets-regex-split