$re = '/(?<=participant id=").*?(?=\")/m';
$str = '<?xml version="1.0" encoding="UTF-8"?>
<recording xmlns="urn:ietf:params:xml:ns:recording" xmlns:ac=http://aaa>
<datamode>complete</datamode>
<group id="00000000-0000-0084-2bb2-880019360e65">
<associate-time>2024-01-30T13:10:49</associate-time>
</group>
<session id="0000-0000-0000-0000-bc3f13048a90ea74">
<group-ref>00000000-0000-0084-2bb2-880019360e65</group-ref>
<associate-time>2024-01-30T13:10:49</associate-time>
</session>
<participant id="+11111111111" session="0000-0000-0000-0000-bc3f13048a90ea74">
<nameID aor=+11111111111@x.x.x.x></nameID>
<associate-time>2024-01-30T13:10:49</associate-time>
<send>00000000-2f30-0084-2bb2-880019360e65</send>
<recv>00000001-42a6-0084-2bb2-880019360e65</recv>
</participant>
<participant id="+22222222222" session="0000-0000-0000-0000-bc3f13048a90ea74">
<nameID aor=+22222222222@y.y.y.y></nameID>
<associate-time>2024-01-30T13:10:49</associate-time>
<send>00000001-42a6-0084-2bb2-880019360e65</send>
<recv>00000000-2f30-0084-2bb2-880019360e65</recv>
</participant>
<stream id="00000000-2f30-0084-2bb2-880019360e65" session="0000-0000-0000-0000-bc3f13048a90ea74">
<label>1</label>
</stream>
<stream id="00000001-42a6-0084-2bb2-880019360e65" session="0000-0000-0000-0000-bc3f13048a90ea74">
<label>2</label>
</stream>
</recording>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php