Online PHP editor | refs for hoiX0

<?php $menu = [ [ 'navigationMenuId' => '1', 'subNavigationItems' => [], ], [ 'navigationMenuId' => '2', 'subNavigationItems' => [], ], [ 'navigationMenuId' => '3', 'subNavigationItems' => [ 4 => [ 'navigationMenuId' => '4', 'subNavigationItems' => [], ], 5 => [ 'navigationMenuId' => '5', 'subNavigationItems' => [], ], 6 => [ 'navigationMenuId' => '6', 'subNavigationItems' => [], ], 7 => [ 'navigationMenuId' => '7', 'subNavigationItems' => [], ], ], ], [ 'navigationMenuId' => '8', 'subNavigationItems' => [], ], [ 'navigationMenuId' => '9', 'subNavigationItems' => [ 10 => [ 'navigationMenuId' => '10', 'subNavigationItems' => [], ], 11 => [ 'navigationMenuId' => '11', 'subNavigationItems' => [], ], 12 => [ 'navigationMenuId' => '12', 'subNavigationItems' => [], ], ], ], [ 'navigationMenuId' => '13', 'subNavigationItems' => [], ], ]; function reindexChildren(array $array): array { foreach ($array as &$item) { if ($item['subNavigationItems']) { $item = reindexChildren($item['subNavigationItems']); } } return array_values($array); } var_export( reindexChildren($menu) );