操纵JSON

Question

我正在开发一个codeigniter应用程序。我需要以这种格式返回的json数据。

 {
        options: [
    {id:"1",text:"test"},
    {id:"2",text:"kabita123"},
    {id:"3",text:"purnima"},
    {id:"4",text:"raju123"},
    {id:"5",text:"saad123"},
    {id:"12",text:"apf123"}
        ]
    }

然而，当返回数据时，我只有这种格式

[{"id":"1","text":"test"},
{"id":"2","text":"kabita123"},
{"id":"3","text":"purnima"},
{"id":"4","text":"raju123"},
{"id":"5","text":"saad123"},
{"id":"12","text":"apf123"}]

我在哪里做错了？我用来生成json数据的代码是

        $users = $this->user_m->get_all();  
        $user_arr = [];
        $i=0;
        foreach ($users as $user) {
            $user_arr[$i] = new stdClass();
            $user_arr[$i]->id = $user->id;
            $user_arr[$i]->text = $user->username;
            $i++;
        }
       //add the header here
        header('Content-Type: application/json');
        echo json_encode( $user_arr );

Answer 1

变化：

echo json_encode( $user_arr );

为：

echo json_encode( array('options' => $user_arr) );