In multidimensional array replace parent element value from child arrays

replace-parent-element-value-from-child-arrays.php

<?php

/**
 * Stackoverflow link https://stackoverflow.com/questions/52388607/in-multidimensional-array-replace-parent-element-value-from-child-arrays
 */

$tree = array(
	'16' => array(
		'id'        => '16',
		'name'      => 'Clothing',
		'count'     => '0',
		'parent_id' => '0',
		'children'  => array(
			'17' => array(
				'id'        => '17',
				'name'      => 'Tshirts',
				'count'     => '5',
				'parent_id' => '16',
			),
			'18' => array(
				'id'        => '18',
				'name'      => 'Hoodies',
				'count'     => '3',
				'parent_id' => '16',
			),
			'19' => array(
				'id'        => '19',
				'name'      => 'Accessories',
				'count'     => '0',
				'parent_id' => '16',
				'children'  => array(
					'31' => array(
						'id'        => '31',
						'name'      => 'Hats',
						'count'     => '2',
						'parent_id' => '19',
					),
					'32' => array(
						'id'        => '32',
						'name'      => 'Belts',
						'count'     => '2',
						'parent_id' => '19',
						'children'  => array(
							'36' => array(
								'id'        => '36',
								'name'      => 'Sub Item',
								'count'     => '4',
								'parent_id' => '32',
							),
						),
					),
				),
			),
		),
	),
	'20' => array(
		'id'        => '20',
		'name'      => 'Music',
		'count'     => '2',
		'parent_id' => '0',
	),
	'21' => array(
		'id'        => '21',
		'name'      => 'Decor',
		'count'     => '3',
		'parent_id' => '0',
	),
);

function modify_tree($tree) {
	$array_iterator = new RecursiveArrayIterator($tree);
	$recursive_iterator = new RecursiveIteratorIterator($array_iterator, RecursiveIteratorIterator::CHILD_FIRST);

	foreach ($recursive_iterator as $key => $value) {
		if (is_array($value) && array_key_exists('children', $value)) {
			$array_with_children = $value;
			$array_with_children_count = $array_with_children['count'];

			foreach ($array_with_children['children'] as $children) {
				$array_with_children_count = $array_with_children_count + $children['count'];
			}

			$array_with_children['count'] = $array_with_children_count;
			$current_depth = $recursive_iterator->getDepth();

			for ($sub_depth = $current_depth; $sub_depth >= 0; $sub_depth--) {
				// Get the current level iterator
				$sub_iterator = $recursive_iterator->getSubIterator($sub_depth);

				// If we are on the level we want to change, use the replacements
				// ($array_with_children) other wise set the key to the parent
				// iterators value
				if ($sub_depth === $current_depth) {
					$value = $array_with_children;
				} else {
					$value = $recursive_iterator->getSubIterator(($sub_depth + 1))->getArrayCopy();
				}

				$sub_iterator->offsetSet($sub_iterator->key(), $value);
			}
		}
	}

	return $recursive_iterator->getArrayCopy();
}

$modified_tree = modify_tree($tree);

echo '<pre>';
print_r($modified_tree);
echo '</pre>';