loop on attributes to create inventory variations

Question

I have this array of attributes for example:

Array
(

    [0] => Array
        (
            [id] => 20
            [title] => Brown
            [parent_id] => 1
            [parent_title] => Color
            [isMultiple] => 1
        )

    [1] => Array
        (
            [id] => 21
            [title] => Cream
            [parent_id] => 1
            [parent_title] => Color
            [isMultiple] => 1
        )

    [2] => Array
        (
            [id] => 61
            [title] => S
            [parent_id] => 2
            [parent_title] => Size
            [isMultiple] => 1
        )

    [3] => Array
        (
            [id] => 62
            [title] => M
            [parent_id] => 2
            [parent_title] => Size
            [isMultiple] => 1
        )

    [4] => Array
        (
            [id] => 63
            [title] => L
            [parent_id] => 2
            [parent_title] => Size
            [isMultiple] => 1
        )

)

from this array we can understand that we have 6 variations of inventory:

1 | Brown | S
2 | Brown | M
3 | Brown | L
4 | Cream | S
5 | Cream | M
6 | Cream | L

1. What is the correct way to loop over this array to create another array of the 6 variations like in the above example.

2. let's assume that I have another 2 attrs in the array like this:

    [5] => Array
        (
            [id] => 64
            [title] => Cotton
            [parent_id] => 3
            [parent_title] => Metiral
            [isMultiple] => 1
        )
   
    [6] => Array
        (
            [id] => 65
            [title] => Wool
            [parent_id] => 3
            [parent_title] => Metiral
            [isMultiple] => 1
        )
   

How I can loop on this array to create variations like these:

1 | Brown | S | wool
2 | Brown | S | cotton
3 | Brown | M | wool
4 | Brown | M | cotton
5 | Brown | L | wool
6 | Brown | L | cotton
7 | Cream | S | wool
8 | Cream | S | cotton
9 | Cream | M | wool
10 | Cream| M | cotton
11 | Cream| L | wool
12 | Cream| L | cotton

Answer 1

OK I found the solution:

A. right, I made an associative arrays of all my attributes:

Array (

[0] => Array
    (
        [0] => 20
        [1] => 21
    )

[1] => Array
    (
        [0] => 61
        [1] => 62
        [2] => 63
    )

)

B. then I recursively create the whole possible variations:

function buildVariants($arrays, $i = 0) {
if (!isset($arrays[$i])) {
    return array();
}
if ($i == count($arrays) - 1) {
    return $arrays[$i];
}

// get combinations from subsequent arrays
$tmp = $this->buildVariants($arrays, $i + 1);

$result = array();

// concat each array from tmp with each element from $arrays[$i]
foreach ($arrays[$i] as $v) {
    foreach ($tmp as $t) {
    $result[] = is_array($t) ? array_merge(array($v), $t) : array($v, $t);
    }
}

return $result;
}    

C. then I add it to tables in this structure:

See tables stru

Answer 2

Maybe start with "cleaning" your data first:

$attr = array();

foreach( $attributes as $attribute ){
  $attr[$attribute['parent_title']][] = $attribute['title'];
} 

So that you have something like

array(
  "Color" => array(
    "Color1",
    "Color2",
    "Color3"
  ),
  "Size" => array(
    "Size1",
    "Size2",
    "Size3"
  ),
  //...
);

From there on this should be helpful:
How to generate in PHP all combinations of items in multiple arrays