php - 为什么 == 操作在 PHP 中的服务器中不起作用，但在 localhost 中起作用？

Question

我将此代码尝试到 localhost 并且它运行良好，但是当我将它上传到服务器时它不起作用并且它有这一行的问题：if($key[$j]== $this->test);. 你能帮我吗 ？:)

<?php
    class key {
        public $test;
        public $result;
        public $imp;
        public $sentc;

        function __construct() {
            $this->test = $_GET['c'];
            $arr = explode("-", $this->test);
            $p = PRODUCTS::getallteedrow();
            $tproduct = PRODUCTS::getAlltaeed();
            $ii = 0;

            for ($i = 0; $i < $p; $i++) {
                $pp = $tproduct[$i];
                $key = $pp['keyword'];
                $key = explode(',', $key);
                $count = count($key);

                for ($j = 0; $j < $count; $j++) {
                    if ($key[$j] == $this->test) {
                        $this->result[$ii] = PRODUCTS::products_SelectRow($pp['id']);
                        $this->sentc = $this->result[$ii]['description'];
                        $this->sentc = explode(" ", $this->sentc);

                        if (count($this->sentc) >= 30) {
                            $this->sentc = array_slice($this->sentc, 0, 30);
                            $this->sentc = implode(" ", $this->sentc);
                            $this->result[$ii]['description'] = $this->sentc . ".....";
                        }

                        echo $this->result[$ii]['description'];
                        $ii++;
                    }
                }
            }
        }
    }
?>

它是 PHP 代码，我在 PHP MVC 中工作。