排序php數組嵌套元素排序

Question

我有一個php會話$ _SESSION ['details']，當我print_r返回以下內容。

Array (
[0] => Array ([nameID] => 1357325402 [vol] => 1 [catID] => 2) 
[1] => Array ([nameID] => 1357325423 [vol] => 1 [catID] => 2) 
[2] => Array ([nameID] => 1357325470 [vol] => 1 [catID] => 10) 
[3] => Array ([nameID] => 1357325440 [vol] => 1 [catID] => 4) 
[4] => Array ([nameID] => 1357325416 [vol] => 1 [catID] => 2) 
[5] => Array ([nameID] => 1357325471 [vol] => 1 [catID] => 10) 
) 

如何對數組進行排序，以便所有的catID在一起？

Array (
[0] => Array ([nameID] => 1357325402 [vol] => 1 [catID] => 2) 
[1] => Array ([nameID] => 1357325423 [vol] => 1 [catID] => 2) 
[2] => Array ([nameID] => 1357325416 [vol] => 1 [catID] => 2) 
[3] => Array ([nameID] => 1357325440 [vol] => 1 [catID] => 4) 
[4] => Array ([nameID] => 1357325470 [vol] => 1 [catID] => 10) 
[5] => Array ([nameID] => 1357325471 [vol] => 1 [catID] => 10) 

) 

Answer 1

試試這個：

function cmp($a, $b){ 
    return strcmp($a["catID"], $b["catID"]); 
} 

usort($_SESSION['details'], "cmp"); 

Answer 2

您可以使用PHP的usort功能，並提供自己的比較函數。像這樣：

function cmp($a, $b) 
{ 
    return ($a["catID"] > $b["catID"]) ? 1 : -1; // Ascending order 
} 

usort($_SESSION[‘details’], "cmp");