问题
I'm in need of a regular expression that can remove unnecessary/extra parenthesis in a string if found.
Example:
Bob Barker LIVE! (((Don't Miss out!)))
Wanted Result:
Bob Barker LIVE! (Don't Miss out!)
I don't care if users you them, as long as they don't over use them, and make sure to close them.
Thanks for any feedback.
回答1:
That's easy enough.
preg_replace('~[\(\)]+~', '', $string);
Edit: I didn't read your whole question. You still want parenthesis, just not duplicates.
preg_replace(array('~\(+~', '~\)+~'), array('(', ')'), $string);
回答2:
You can do this effectively with regex + recursion. Do this until it stops doing anything:
s/\(\([^()]*)\)\)/\(\1\)/g
Now some comments:
1) I'm leaving it to you to convert sed/perl style into PHP style regex.
2) It's hard to read because ( ) are special characters. Basically I'm saying "replace every ((...)) with (...) as long as ... doesn't contain any ( or ). And to be honest I didn't test the mess I wrote down, but with this idea you should be able to repair.
This always removes them in pairs.
Basically the moral here is: you asked a question you can't do with a simple regex - removing in pairs requires more state than the language permits. But this one is low-hanging fruit if you iterate over the simple regex and eat the doubles from inside-out.
回答3:
Try this:
preg_replace( '/\(+(.*?)\)+/', '($1)', 'Bob Barker LIVE! (((Don\'t Miss out!)))');
Demo
回答4:
This won't work properly for nested parentheses, but that's really difficult to get right with regex (and depending on the engine even impossible):
preg_replace(array('/\(+/', '/\)+/'), array('(', ')'), $text);
回答5:
You can try this :
preg_replace("([\\(]{1,})", "(", preg_replace("([\\)]{1,})", ")", $your_string));
来源：https://stackoverflow.com/questions/10999835/regular-expression-to-remove-multiple-parenthesis