- preg_match: documentation ( source)
<?php
$n = "Chan";
$str = ")24.231.23.2 " + $n + ":";
preg_match("/\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3} " . $n . "/", $str, $m);
echo $m;
//str_replace(" " + $n, "", $m[0], $r);
//$ip = $r[0]; // Should return 24.231.23.2
//echo $ip;