PHP二维数组排序

$arr = array(
    array(
        "a" => 1,
        "b" => 2
    ),
    array(
        "a" => 3,
        "b" => 4
    ),
    array(
        "a" => 5,
        "b" => 6
    )
);  

echo "<pre>";
echo "按照a字段来排：";
var_dump(dArraySort($arr, "a" , 0));  

// 二维数组排序
// $arr 要排序的数组
// $keyName 要参照的第二维的KEY
// $desc 排序 0正序 1逆序
function dArraySort($arr, $keyName , $desc=0)
{
    if (!is_array($arr))
    {
            return $arr;
    }

    foreach($arr AS $key => $row)
    {
            $temp[$key] = $row[$keyName];
    }
    if($desc==1)
        array_multisort($temp, SORT_DESC,$arr);
    else
        array_multisort($temp, SORT_ASC,$arr);
    return $arr;
}