Array values always get overriden by the last key inside foreach - php

Question

There's a following array:
$input = [
'adults' => [1, 2],
'children' => [3, 4]
];
The number of keys and values might be dynamic in this array (but the structure, key => Numeric:Array always remains the same).
I want to turn this array into the following structure:
[
[
'adults' => 1,
'children' => 3
],
[
'adults' => 2,
'children' => 4
]
]
In order to achieve this, I wrote the following function:
function parse(array $input)
{
$output = [];
$keys = array_keys($input);
foreach ($input as $parameter => $values) {
$internal = [];
foreach ($values as $value) {
foreach ($keys as $key) {
if (!isset($internal[$key])) {
$internal[$key] = $value;
}
}
}
$output[] = $internal;
}
return $output;
}
But this gives an unxpected output:
print_r(parse($input));
Array
(
[0] => Array
(
[adults] => 1
[children] => 1
)
[1] => Array
(
[adults] => 3
[children] => 3
)
)
Somehow the values always get overriden by the last one inside the parsing function. So what might cause this error?

Answer 1

If I understand the logic correctly, this should work:
function parse(array $input)
{
$output = [];
foreach ($input as $key1 => $values) {
foreach ($values as $key2 => $value) {
$output[$key2][$key1] = $value;
}
}
return $output;
}
https://3v4l.org/HeXUp
With a larger array
$input = [
'adults' => [1, 2],
'children' => [3, 4],
'foo' => [2, 7],
'bar' => [4, 6],
];
This returns
Array
(
[0] => Array
(
[adults] => 1
[children] => 3
[foo] => 2
[bar] => 4
)
[1] => Array
(
[adults] => 2
[children] => 4
[foo] => 7
[bar] => 6
)
)