二维数组排序

<?php
$users = array(
array('id'=>1,'age'=>'12'),
array('id'=>2,'age'=>'13'),
array('id'=>3,'age'=>'44'),
array('id'=>4,'age'=>'22'),
array('id'=>5,'age'=>'11'));
$ages = array();
foreach ($users as $key => $val) {
    $ages[] = $val['age'];
}
  echo "<pre>";
print_r($ages);
 //升序排列age,按照age的顺序排列$users
array_multisort($ages, SORT_ASC, $users);

print_r($users);
//使用这个方法，会比较麻烦些，要将age提取出来存储到一维数组里，然后按照age升序排列。
/*执行后，$users就是排序好的数组了，可以打印出来看看。如果需要先按年龄升序排列，再按照ID升序排列，方法同上，就是多提取一个名称数组出来，最后的排序方法这样调用
代码如下:array_multisort($ages, SORT_ASC, $ID, SORT_ASC, $users);*/
/*(
    [0] => 12
    [1] => 13
    [2] => 44
    [3] => 22
    [4] => 11
)
Array
(
    [0] => Array
        (
            [id] => 5
            [age] => 11
        )

    [1] => Array
        (
            [id] => 1
            [age] => 12
        )

    [2] => Array
        (
            [id] => 2
            [age] => 13
        )

    [3] => Array
        (
            [id] => 4
            [age] => 22
        )

    [4] => Array
        (
            [id] => 3
            [age] => 44
        )

)*/