php问题，nothing_here没有输出吗？

Question

<?php
$city  = "San Francisco";
$state = "CA";
$event = "SIGGRAPH";

$location_vars = array("city", "state");

$result = compact("event", "nothing_here", $location_vars);
print_r($result);
?>

以上例程会输出：

Array
(

[event] => SIGGRAPH
[city] => San Francisco
[state] => CA

)

Answer 1

你看下compact的定义啊！变量不存在，他怎么输出啊……