按嵌套元素排序php数组

Question

我有一个php会话$ _SESSION ['details']当我print_r返回以下内容时。

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 ) 
 )

如何对数组进行排序以使所有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

试试这个：

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

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

Answer 2

您可以使用PHP的usort功能并提供您自己的比较功能。像这样：

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

usort($_SESSION[‘details’], "cmp");