Research on PHP two dimensional array sorting

> function takes two dimensional array sorting:

The array format is as follows:

$goods = array(
    0 => array(
        “id”=>1,
        “tag”=>array(
            “price”=>”10”,
            “old_price”=>”20”
         )
    ),
    1 => array(
        “id”=>2,
        “tag”=>array(
            “price”=>”30”,
            “old_price”=>”100”
        )
    ),
    2 => array(
        “id”=>3,
        “tag”=>array(
            “price”=>”25”,
            “old_price”=>”70”
        )
    ),
    3 => array(
        “id”=>4,
        “tag”=>array(
            “price”=>”15”,
            “old_price”=>”50”
        )
    )
);            

$goods > is a collection of goods, each commodity with one.id,tag > is the specification of the commodity.price is the selling price of goods.old_price

$sort_arr = array();

foreach($goods as $key => &$val){

    foreach($val[‘tag’ as $k => $v]{

        $val[‘goods_arr’][] = array(“price”=>$v[“price”],”old_price”=>$v[“old_price”]);

    })

    foreach($val[‘goods_arr’] as $v){

        $sort_arr[] = $v[‘price’];

    }

    array_multisort($sort_arr_sort,SORT_ASC,$val['goods_arr']);
    $val['price_min'] = $val['goods_arr'][0]['price'];
    $val['old_price_min'] = $val['goods_arr'][0][‘old_price’];
				
    array_multisort($discount_sort,SORT_DESC,$val['goods_arr']);
    $val['price_max'] = $val['goods_arr'][0]['price'];
    $val['old_price_max'] = $val['goods_arr'][0]['old_price'];

}