php - recreate array from flat to multidimensional?

[duckduckgoose]

I am trying to take a flat array and recreate it so that it's multidimensional. I've been looking into array_combine and array_merge, but I'm not sure that either of those will give me what I'm hoping for...

The array, in it's current form (and this is just a simplified example):

Array
(
    [0] => stdClass Object
        (
            [tid] => 31
            [name] => Safeway
            [parents] => Array
                (
                    [0] => 0
                )

    )

[1] => stdClass Object
    (
        [tid] => 32
        [name] => Dairy
        [parents] => Array
            (
                [0] => 31
            )

    )

[2] => stdClass Object
    (
        [tid] => 33
        [name] => Milk
        [parents] => Array
            (
                [0] => 32
            )

    )
)

I'm trying to create a multidimensional array where each object is a subarray of it's parent. So, in the example above, I'm trying to output:

Array
(
    [0] => stdClass Object
        (
            [tid] => 31
            [name] => Safeway
            [children] => Array
                (
                    [tid] => 32
                    [name] => Dairy
                    [children] => Array
                        (
                            [tid] => 33
                            [name] => Milk
                        )
                )

    )
)

[johanafm]

One question is if you really want to get rid of your objects. And if you do, why you don't want to get rid of the one residing in Array[0].
Also, I would have expected the name Object->parent, containing the id of the parent, Object->parents is an array. What is the purpose of this? Is this real life ancestry, so that each child has two parents? Or is parents an array containing a complete ancestry in a tree where each child has only one parent?

Anyway, assuming there is only one parent, the easiest way of achieving a multidimensional array is probably like this

# get rid of your objects and use tid as array key.
$flat = array();
foreach($orig as $o) {
	$flat[$o->tid]['tid'] = $o->tid;
	$flat[$o->tid]['name'] = $o->name;
	$flat[$o->tid]['parent'] = $o->parent;
}

# $new will only contain top level elements.
# $flat will no longer be flat.
$new = array();
foreach($flat as $k => $v) {
	if ($v['parent'] == 0) {
		$new[$v['tid']] = &$flat[$k];
	}
	else
		$flat[$v['parent']]['children'][] = &$flat[$k];

This should be modifiable to match the actual functionality of your parents array.