jons格式有关问题 如何数值型有带单引号如何去掉

jons格式问题 怎么数值型有带单引号怎么去掉
怎么去掉单引号
$arr=array('as'=>1,'data'=>array('ID'=>$r_id,'List'=>$zfc));
echo json_encode($arr,JSON_FORCE_OBJECT);
{
"as": 1,
"data": {
"ID": "111",
"NeedImgList": "1.jpg,2.jpg"
}
}

怎么把ID 中"111" 的双引号去掉？？？
------解决思路----------------------

$r_id = 111;
$zfc = '123';
$arr=array('as'=>1,'data'=>array('ID'=>$r_id,'List'=>$zfc));
echo json_encode($arr,JSON_FORCE_OBJECT 
------解决思路----------------------
 JSON_PRETTY_PRINT);

{
    "as": 1,
    "data": {
        "ID": 111,
        "List": "123"
    }
}

$arr=array('as'=>1,'data'=>array('ID'=>intval($r_id),'List'=>$zfc));
echo json_encode($arr,JSON_FORCE_OBJECT);

$arr=array('as'=>1,'data'=>array('ID'=>$r_id+0,'List'=>$zfc));
echo json_encode($arr,JSON_FORCE_OBJECT);