php 按两个标准对对象进行排序？

Question

尝试根据 (1) 深度和 (2) 权重对这个对象数组进行排序，但不确定如何修改我正在使用的函数以包含其他级别...

我正在使用这个函数:

function cmp( $a, $b ) {
    if(  $a->weight ==  $b->weight ){
        return 0 ;
    }
    return ($a->weight < $b->weight) ? -1 : 1;
}

然后这样做:

$menu = get_tree(4, $tid, -1, 2);
usort($menu, 'cmp');

这将根据权重对数组进行准确排序，但我需要添加另一个级别的排序。这样数组先按深度排序，再按权重排序。

因此，如果原始数组如下所示:

    Array
(
    [0] => stdClass Object
        (
            [tid] => 24
            [name] => Sample
            [weight] => 3
            [depth] => 0
        )

    [1] => stdClass Object
        (
            [tid] => 66
            [name] => Sample Subcategory
            [weight] => 0
            [depth] => 1
        )

    [2] => stdClass Object
        (
            [tid] => 67
            [name] => Another Example
            [weight] => 1
            [depth] => 0
        )

    [3] => stdClass Object
        (
            [tid] => 68
            [name] => Subcategory for Another Example
            [weight] => 1
            [depth] => 1
        )

    [4] => stdClass Object
        (
            [tid] => 22
            [name] => A third example master category
            [weight] => 0
            [depth] => 0
        )

我可以先按深度排序，然后按权重排序，结果如下所示:

Array
(
    [0] => stdClass Object
        (
            [tid] => 22
            [name] => A third example master category
            [weight] => 0
            [depth] => 0
        )

    [1] => stdClass Object
        (
            [tid] => 67
            [name] => Another Example
            [weight] => 1
            [depth] => 0
        )

    [2] => stdClass Object
        (
            [tid] => 24
            [name] => Sample
            [weight] => 3
            [depth] => 0
        )

    [3] => stdClass Object
        (
            [tid] => 66
            [name] => Sample Subcategory
            [weight] => 0
            [depth] => 1
        )

    [4] => stdClass Object
        (
            [tid] => 68
            [name] => Subcategory for Another Example
            [weight] => 1
            [depth] => 1
        )

Answer 1

function cmp( $a, $b )
{
  if ($a->depth == $b->depth)
  {
    if($a->weight == $b->weight) return 0 ;
    return ($a->weight < $b->weight) ? -1 : 1;
  }
  else
    return ($a->depth < $b->depth) ? -1 : 1;
}