php array merge recursive with same array values and create combinations - php

Question

Hello i am new in php and I just stuck in brainstorming array, I have below php array
[0] => Array
(
[0] => Array
(
[1] => 5
[2] => 12
[11] => 15
)
[1] => Array
(
[1] => 5
[2] => 12
[11] => 16
)
[2] => Array
(
[1] => 4
[2] => 9
[11] => 15
)
[3] => Array
(
[1] => 3
[2] => 9
[11] => 15
)
[4] => Array
(
[1] => 3
[2] => 9
[11] => 16
)
[5] => Array
(
[1] => 3
[2] => 13
[11] => 15
)
[6] => Array
(
[1] => 3
[2] => 13
[11] => 16
)
[7] => Array
(
[1] => 3
[2] => 12
[11] => 15
)
[8] => Array
(
[1] => 3
[2] => 12
[11] => 16
)
[9] => Array
(
[1] => 4
[2] => 9
[11] => 16
)
[10] => Array
(
[1] => 4
[2] => 13
[11] => 15
)
[11] => Array
(
[1] => 4
[2] => 13
[11] => 16
)
[12] => Array
(
[1] => 4
[2] => 12
[11] => 15
)
[13] => Array
(
[1] => 4
[2] => 12
[11] => 16
)
[14] => Array
(
[1] => 5
[2] => 9
[11] => 15
)
[15] => Array
(
[1] => 5
[2] => 13
[11] => 16
)
)
And I want below out put
[0]=> Array
(
[5]=> Array
(
[12]=> Array
(
[0] => 15
[1] => 16
)
[9]=> Array
(
[0] => 15
)
[13]=> Array
(
[0] => 16
)
)
[4]=> Array
(
[9]=> Array
(
[0] => 15
[1] => 16
)
[13]=> Array
(
[0] => 16
)
[12]=> Array
(
[0] => 15
[1] => 16
)
)
[3]=> Array
(
[9]=> Array
(
[0] => 15
[1] => 16
)
[13]=> Array
(
[0] => 15
[1] => 16
)
[12]=> Array
(
[0] => 15
[1] => 16
)
)
)
Sorry out put not much clear but I want check each array first common value e.g 5,4, and 3 then based on these value traverse though each value and create tree array
As Example simple i want each arrays first element and then recursively array check values and create new
Example have just 3 level but i want recursive n-level and , help would be Appreciate.

Answer 1

Not sure if I understand correctly as the samples are not explained clearly but I somehow was able to print the desired output. Explanations given thru comments
// I just simplified your given array
$input[0] = array(
[1 => 5, 2 => 12, 11 => 15],
[1 => 5, 2 => 12, 11 => 16],
[1 => 4, 2 => 9, 11 => 15],
[1 => 3, 2 => 9, 11 => 15],
[1 => 3, 2 => 9, 11 => 16],
[1 => 3, 2 => 13, 11 => 15],
[1 => 3, 2 => 13, 11 => 16],
[1 => 3, 2 => 12, 11 => 15],
[1 => 3, 2 => 12, 11 => 16],
[1 => 4, 2 => 9, 11 => 16],
[1 => 4, 2 => 13, 11 => 15],
[1 => 4, 2 => 13, 11 => 16],
[1 => 4, 2 => 12, 11 => 15],
[1 => 4, 2 => 12, 11 => 16],
[1 => 5, 2 => 9, 11 => 15],
[1 => 5, 2 => 13, 11 => 16]
);
// Declare new output array
$output[0] = [];
// Loop thru each array inside $input[0] array
foreach($input[0] as $key => $value) {
// Set each array value to variables
$one = $value[1];
$two = $value[2];
$eleven = $value[11];
// Check if $one key already exist, create if not
if (!isset($output[0][$one])) {
$output[0][$one] = [];
}
// Check if $two key already exist, create if not
if (!isset($output[$one][$two])) {
$output[0][$one][$two] = [];
}
// push each $eleven
$output[0][$one][$two][] = $eleven;
};
// Prints output array
echo '<pre>';
print_r($output);

Answer 2

To accommodate situations where you have multiple first-level elements, use a loop. Use another loop to iterate each entry. You can even use array destructuring inside the nested foreach() to declare variables.
Code: (Demo)
$result = [];
foreach ($input as $key => $array) {
foreach ($array as [1 => $one, 2 => $two, 11 => $eleven]) {
$result[$key][$one][$two][] = $eleven;
}
}
var_export($result);
There is no need to declare/assign parent keys to append data into them. There are deliberately no conditions in my snippet.