接口返回值中数组中包含多个json对象形式

返回数据Json：
 {
    “code”: ,
    ”msg”: ”成功”,
    ”departmentlist”: [
        {
            "id": "",
            "name": "软件部"

        }
    ],
    ”userlist”: [
        {
            "id": "",
            "headiconurl": "用户头像地址",
            "truename": "姓名",
            "positionname": "职位"
        }
    ]
}

php接口代码

        前面的查询符合条件sql语句已省略. 

         $arr=array();
         $arr['code']=200;
         $arr['msg']='成功';
         $arr['departmentlist'][]=array(
                'id'=>$dept['id'],
                'name'=>$dept['name'],
            );
         foreach($deptmember as $key=>$val) {

             $arr['userlist'][] = array(
                 'id' => $val['id'],
                 'headiconurl' => $val['face'],
                 'truename' => $val['name'],
                 'positionname' => $val['ranking'],
             );
         }
        echo json_encode($arr,true);