跪求一个正则表达式

Question

我想把网页中的链接 http://www.xiha.com/detail.php?/iid/c84212cf855470372d7bca69c3f7b413
变为 http://c84212cf855470372d7bca69c3f7b413.xiha.com请教怎么用正则表达式替换，谢谢，我下面写的是错误的，新手求指教！
$regs[1] = preg_replace("/http://www.xiha.com/detail.php?/iid/(.*)\"/iU","http://$1.xiha.com",$regs[1]);

Answer 1

$str = 'http://www.xiha.com/detail.php?/iid/c84212cf855470372d7bca69c3f7b413';$result = preg_replace("/http:\/\/www\.xiha\.com\/detail.php\?\/iid\/(.*)/i", "http://\\1.xiha.com",$str);
echo $result;

Answer 2

<?php
$str = 'http://www.xiha.com/detail.php?/iid/c84212cf855470372d7bca69c3f7b413';
$str = preg_replace("#^http://www.xiha.com/detail.php\?/iid/(\w+)$#i","http://$1.xiha.com",$str);
var_dump($str);
?>