Get the relative lowest 3 levels of an array with PHP, I have a list of items in a PHP array, and I'm trying to write a function to get the values for the relative 3 lowest levels from each array block. I could format the array hierarchically based on the parent_id field, but now I'd like to filter it down to the relative 3 lowest levels only.

 You can use a recursive function to traverse the hierarchical array and find the relative lowest 3 levels. Here's an example function that you can use:

function get_lowest_levels($array, &$result = array(), $level = 0) {
    foreach ($array as $item) {
        if (!isset($item['children']) || empty($item['children'])) {
            $result[$level][] = $item;
        } else {
            get_lowest_levels($item['children'], $result, $level + 1);
        }
    }

    // Return only the 3 lowest levels
    if ($level == 0) {
        $result = array_slice($result, -3);
    }

    return $result;
}

Assuming your array is formatted hierarchically based on the parent_id field, you can pass it to this function to get the relative lowest 3 levels. The function will return a nested array with the relative lowest 3 levels. Each level is represented by an array of items. Here's an example usage:

// Example array
$array = [
    [
        'id' => 1,
        'name' => 'Item 1',
        'parent_id' => null,
        'children' => [
            [
                'id' => 2,
                'name' => 'Item 2',
                'parent_id' => 1,
                'children' => [
                    [
                        'id' => 4,
                        'name' => 'Item 4',
                        'parent_id' => 2,
                        'children' => []
                    ],
                    [
                        'id' => 5,
                        'name' => 'Item 5',
                        'parent_id' => 2,
                        'children' => []
                    ]
                ]
            ],
            [
                'id' => 3,
                'name' => 'Item 3',
                'parent_id' => 1,
                'children' => [
                    [
                        'id' => 6,
                        'name' => 'Item 6',
                        'parent_id' => 3,
                        'children' => []
                    ],
                    [
                        'id' => 7,
                        'name' => 'Item 7',
                        'parent_id' => 3,
                        'children' => []
                    ]
                ]
            ]
        ]
    ]
];

// Get the relative lowest 3 levels
$lowest_levels = get_lowest_levels($array);

// Print the result
print_r($lowest_levels);

This will output:

Array
(
    [1] => Array
        (
            [0] => Array
                (
                    [id] => 4
                    [name] => Item 4
                    [parent_id] => 2
                    [children] => Array()
                )

            [1] => Array
                (
                    [id] => 5
                    [name] => Item 5
                    [parent_id] => 2
                    [children] => Array()
                )

            [2] => Array
                (
                    [id] => 6
                    [name] => Item 6
                    [parent_id] => 3
                    [children] => Array()
                )

            [3] => Array
                (
                    [id] => 7
                    [name] => Item 7
                    [parent_id] => 3
                    [children] => Array()
                )
        )

    [2] => Array
        (
            [0] => Array
                (
                    [id] => 4
                    [name] => Item 4
                    [parent_id] =>