Question

I have a string of numbers surrounded by parenthesis:

(2)(56)(9)(12)(2)

I was given the following regex by someone to split the numbers out of their parentheses:

<?php

$string = '(2)(56)(9)(12)(2)';

$pattern = "/\\)\\(|\\(|\\)?/";

$numbers = preg_split($pattern, $string);

foreach ($numbers as $number) {
    echo $number.'<br />';
}

?>

This outputs:

<br />
<br />
2<br />
<br />
5<br />
6<br />
<br />
9<br />
<br />
1<br />
2<br />
<br />
2<br />
<br />
<br />

When I really need it to output:

2<br />
56<br />
9<br />
12<br />
2<br />

How can the regex be altered to make it work?

p.s. each number in between the parenthesis can be of an unlimited length.

Answer 1

You just need the PREG_SPLIT_NO_EMPTY option of preg_split, and a small change in the pattern:

$pattern = "/\\)\\(|\\(|\\)/"; // removed the "?"
$numbers = preg_split($pattern, $string, -1, PREG_SPLIT_NO_EMPTY); // added PREG_SPLIT_NO_EMPTY

Or use preg_match:

$string = '(2)(56)(9)(12)(2)';

preg_match_all('#\d+#', $string, $matches);

foreach ($matches[0] as $number) {
    echo "$number<br />\n";
}

Output:

2<br />
56<br />
9<br />
12<br />
2<br />