javascript操作json

for (var i = 0; i < selectedPartList.length; i++) {
            if (selectedPartList[i].vpart_code == jsonRow.vpart_code) {
                selectedPartList.splice(i, 1);//删除一项
            }
        }
        if (quantity != "0") {
            jsonRow.vused_qty = quantity;
            selectedPartList.push(jsonRow);//添加一项
        }