I have two type of strings in one text:
a(bc)de(fg)h
a(bcd(ef)g)h
I need to get text between first level parentheses. In my example this is:
bc
fg
bcd(ef)g
I tried to use next regular expression /\((.+)\)/ with Ungreedy (U) flag:
bc
fg
bcd(ef
And without it:
bc)de(fg
bcd(ef)g
Both variants don't do what I need. Maybe someone know how solve my issue?
This question pretty much has the answer, but the implementations are a little ambiguous. You can use the logic in the accepted answer without the ~s to get this regex:
\(((?:\[^\(\)\]++|(?R))*)\)
Tested with this output:
Use PCRE Recursive pattern to match substrings in nested parentheses:
$str = "a(bc)de(fg)h some text a(bcd(ef)g)h ";
preg_match_all("/\((((?>[^()]+)|(?R))*)\)/", $str, $m);
print_r($m[1]);
The output:
Array
(
[0] => bc
[1] => fg
[2] => bcd(ef)g
)
\( ( (?>[^()]+) | (?R) )* \)
First it matches an opening parenthesis. Then it matches any number of substrings which can either be a sequence of non-parentheses, or a recursive match of the pattern itself (i.e. a correctly parenthesized substring). Finally, there is a closing parenthesis.
Technical cautions:
If there are more than 15 capturing parentheses in a pattern, PCRE has to obtain extra memory to store data during a recursion, which it does by using pcre_malloc, freeing it via pcre_free afterwards. If no memory can be obtained, it saves data for the first 15 capturing parentheses only, as there is no way to give an out-of-memory error from within a recursion.
Please can you try that:
preg_match("/\((.+)\)/", $input_line, $output_array);
Test this code in http://www.phpliveregex.com/
Regex: \((.+)\)
Input: a(bcd(eaerga(er)gaergf)g)h
Output: array(2
0 => (bcd(eaerga(er)gaergf)g)
1 => bcd(eaerga(er)gaergf)g
)
