CI控制器中设置在其它方法中可用的变量

class User extends CI_Controller{

    public function __construct()
    {
        parent::__construct();

        $arr = array(
                ‘1‘ => ‘one‘,
                ‘2‘ => ‘two‘,
                ‘3‘ => ‘three‘,
            );
        $this->load->vars($arr);
    }
    public function index()
    {
        // 输出 string ‘two‘ (length=3)
        var_dump($this->load->get_var(‘2‘));
    }
}