Question

Array(
[1] => put returns (between) paragraphs
[2] => (for) linebreak (add) 2 spaces at end
[3] => indent code by 4 (spaces!)
[4] => to make links
)

Want to get text inside brackets (for each value):

1. take only first match
2. remove this match from the value
3. write all matches to new array

After function arrays should look like:

Array(
[1] => put returns paragraphs
[2] => linebreak (add) 2 spaces at end
[3] => indent code by 4
[4] => to make links
)
Array(
[1] => between
[2] => for
[3] => spaces!
[4] => 
)

What is the solution?

Answer 1

I would use the regular expression /\((\([^()]*\)|[^()]*)\)/ (this will match one or two pairs of parentheses) together with preg_split:

$matches = array();
foreach ($arr as &$value) {
    $parts = preg_split('/\((\([^()]*\)|[^()]*)\)/', $value, 2, PREG_SPLIT_DELIM_CAPTURE);
    if (count($parts) > 1) {
        $matches[] = current(array_splice($parts, 1, 1));
        $value = implode('', $parts);
    }
}

Using preg_split with PREG_SPLIT_DELIM_CAPTURE flag set will contain the matched separators in the result array. So a match was found, there are at least three parts. In that case the second member is the one we are looking for. That member is removed with array_splice that does also return the array of removed members. To get the removed member, current is used on the return value of array_splice. The remaining members are then put back together.