php二维数组根据某个字段排序

排序函数： 

public function f_order($arr,$field,$sort){
    $order = array();
    foreach($arr as $kay => $value){
        $order[] = $value[$field];
    }
    if($sort==1){
        array_multisort($order,SORT_ASC,$arr);
    }else{
        array_multisort($order,SORT_DESC,$arr);
    }
    return $arr;
}


$data = $this->f_order($data,'days','2');// 2是排序，1是正序