正则表达式

Question

$s = 'http://www.qq.show.php?act=sub&id=7&ucode=o0Fm6jnHRJvmSEM8fpYGS7N_3fNU我想获取o0Fm6jnHRJvmSEM8fpYGS7N_3fNU这个怎么写
如果是这样呢：
http://www.qq.show.php?act=sub&id=7&ucode=o0Fm6jnHRJvmSEM8fpYGS7N_3fNU&q=4
获取o0Fm6jnHRJvmSEM8fpYGS7N_3fNU这个值';preg_match_all('/(?<=ucode=).+?\b/', $s, $m);
print_r($m);
Array
(
    [0] => Array
        (
            [0] => o0Fm6jnHRJvmSEM8fpYGS7N_3fNU
            [1] => o0Fm6jnHRJvmSEM8fpYGS7N_3fNU
        ))