Modifying N-dimensional array PHP - php

Question

how can I add an extra dimesion before each element in N-dimensional array (recursively)? Let's say I have
Array
(
[room] => Array
(
[bed] = Array
(
[material] => wood
)
)
)
And I want to add an extra "[0]" dimension before room, bed and material. (Adding dimension only if the last element is an array). I also want to distinguish, if there already is the extra [0] dimension, so it will not appear twice .. + I don't want to add [0] if the array key is named "#attribute".
I'm trying to figure it out, but I'm really lost. This is what I've got so far..
function normalize_array (&$array) {
if (is_array($array)) {
if (!isset($array[0])) {
$array = array ( "0" => $array);
}
foreach ($array[0] as $next) {
normalize_array ($next);
}
}
}
but it does not work recursively. Any help will be appreciated. Thanks!

Answer 1

From the documentation of foreach:
In order to be able to directly modify array elements within the loop
precede $value with &. In that case the value will be assigned by reference.
So if you modify your function like this, it works:
function normalize_array (&$array) {
if (is_array($array)) {
if (!isset($array[0])) {
$array = array ( "0" => $array);
}
foreach ($array[0] as &$next) { // <-- add & here
normalize_array ($next);
}
}
}

Answer 2

Possible solution (tested just a little, but seems to work):
function normalize_array($array, $keys){
$new = array();
foreach($array as $key => $value){
if (in_array($key, $keys) && is_array($value)){
$new["0"] = array($key => normalize_array($value, $keys));
} else {
$new[$key] = $value ;
}
}
return $new ;
}
$data = array(
"room" => array(
"bed" => array(
"material" => "wood"
)
)
);
$keys = array("room", "bed", "material");
$new = normalize_array($data, $keys);
var_dump($new);

Answer 3

Final solution:
function normalize_array_rec (&$array) {
if (is_array($array)) {
if (!isset($array[0])) {
$array = array ( "0" => $array);
}
$i = 0;
while (isset($array[$i])) {
foreach ($array[$i] as &$next) {
normalize_array_rec ($next);
}
$i++;
}
}
}
Forgot to call function in each instance of array, not only in [0] index.