关于 array_pad函数的疑问

[杰]

<?php
$city=array('li','yang','wang');
array_pad($city,5,'xie');
foreach($city as $value)
{
	print $value;
}
?>

为什么输出结果是“liyangwang”
不应该是”liyangwangxiexie“吗

[xuzuning]

$city = array_pad($city,5,'xie');