foreach循环的{$key}键值，为什么都是最后那一个数组的键值
传去模版的变量数组
$list = [
"user1" =>["username"=>"1","email" => "123"],
"user2" =>["username"=>"2","email" => "456"],
"user3" =>["username"=>"3","email" => "789"]
];
模版的foreach
{foreach $list as $k }
<p>{$key}</p>
{/foreach}
结果
user3:1:123
user3:2:456
user3:3:789
然后那个{$key} 循环了三次，为什么键值都是user3
而不是user1 user2 user3
