Find parentheses

[tobeyt323]

Find and match all parentheses with open and close and weed out any that dont match

 

$string = "(()))(()";

 

How do i accomplish this?

[Jacques1]

Use a stack. Opening parentheses (or their indexes) get pushed onto the stack; whenever you encounter a closing paranthesis, you pop the stack.

 

Is this homework?

Edited February 9, 2017 by Jacques1

[requinix]

Weed out any strings that don't match? Match an opening parentheses, use (?R)* for recursion, and match a closing parenthesis, then check that what you found was the entire string.

If you want to weed out any parentheses that don't match then it depends how you want to report on what didn't match...