PHP - (Almost) Flatten multidimensional array recursively - php

Question

I am trying to change the following array to an almost flat array. So id 4 would be in the first level of the array, as would id 6 and 5, but still have their own index so I can tell which page is which. But with the same order as they have now. I presume that the solution would be some sort of recursive PHP function but I haven't a clue how to do this.
Array
(
[0] => Array
(
[id] => 2
[identifier] => External URL
[parent] => 0
[sortOrder] => 1
[depth] => 0
)
[1] => Array
(
[id] => 3
[identifier] => First Team
[parent] => 0
[sortOrder] => 2
[depth] => 0
[children] => Array
(
[0] => Array
(
[id] => 4
[identifier] => League tables
[parent] => 3
[sortOrder] => 0
[depth] => 1
[children] => Array
(
[0] => Array
(
[id] => 6
[identifier] => British and Irish Cup Tables
[parent] => 4
[sortOrder] => 24
[depth] => 2
)
[1] => Array
(
[id] => 5
[identifier] => Greene King IPA Championship
[parent] => 4
[sortOrder] => 25
[depth] => 2
)
)
)
)
)
[2] => Array
(
[id] => 1
[identifier] => Home
[parent] => 0
[sortOrder] => 25
[depth] => 0
)
)

Answer 1

<?php
$data = [
[
'id' => 1,
'name' => 'one',
'children' =>
[
[
'id' => 2,
'name' => 'two',
'children' =>
[
[
'id' => 4,
'name' => 'four'
]
]
],
[
'id' => 3,
'name' => 'three',
'children' =>
[
[
'id' => 5,
'name' => 'five'
]
]
]
]
],
[
'id' => 6,
'name' => 'six'
]
];
$stanley = [];
$flatten = function(array $data) use (&$flatten, &$stanley) {
foreach($data as $k => $v) {
if(isset($v['children'])) {
$flatten($v['children']);
unset($v['children']);
}
$stanley[] = $v;
}
};
$flatten($data);
var_export($stanley);
Output:
array (
0 =>
array (
'id' => 4,
'name' => 'four',
),
1 =>
array (
'id' => 2,
'name' => 'two',
),
2 =>
array (
'id' => 5,
'name' => 'five',
),
3 =>
array (
'id' => 3,
'name' => 'three',
),
4 =>
array (
'id' => 1,
'name' => 'one',
),
5 =>
array (
'id' => 6,
'name' => 'six',
),
)

Answer 2

I have found the solution! I built a recursive PHP function which utilised the depth index to track which level each of the items are while still keeping the array flat (ish).
function dropdownNavigationTree($array) {
$response = [];
foreach($array as $page) {
if (!is_array($page['children'])) {
$response[$page['id']] = ($page['depth'] > 0 ? str_repeat("-", $page['depth']).' ' : FALSE).$page['identifier'];
} else {
$response[$page['id']] = ($page['depth'] > 0 ? str_repeat("-", $page['depth']).' ' : FALSE).$page['identifier'];
$children = dropdownNavigationTree($page['children']);
$response = $response + $children;
}
}
return $response;
}