PHP数组 按照某个元素排序

按照 flag 排序：

$arr[] = array("name"=>"a","flag"=>1);
$arr[] = array("name"=>"b","flag"=>2);
$arr[] = array("name"=>"a","flag"=>1);
$flag=array();
foreach($arr as $arr2){
    $flag[]=$arr2["flag"];
    }
array_multisort($flag, SORT_ASC, $arr);
print_r($arr);

结果：

Array ( [0] => Array ( [name] => a [flag] => 1 ) [1] => Array ( [name] => a [flag] => 1 ) [2] => Array ( [name] => b [flag] => 2 ) )