Tree traversal in PHP

categories.php

<?php

$recursive_array = array(
  0 => array(
    'name' => 'pets',
    'category' => array(
      0 => array(
        'name' => 'cats',
        'category' => array(
          0 => array(
            'name' => 'big cats',
            'category' => array(
              0 => array(
                'name' => 'fat cats'
              ),
              1 => array(
                'name' => 'ill cats'
              )
            )
          ),
          1 => array(
            'name' => 'small cats'
          )
        )
      ),
      1 => array(
        'name' => 'ponies'
      )
    )
  )
)

$catgroups = array();
$cats = array();

function traverse_cats(&$sub_array, $parent) {
  global $catgroups, $cats;

  foreach ($sub_array as &$sub) {
    if (isset($sub['category'])) {
      $catgroups[$sub['name']] = $parent;
      traverse_cats($sub['category'], $sub['name']);
    }
    $cats[$sub['name']] = $parent;
  }
}

traverse_cats($recursive_array, 'root');

?>

Thanks, this really helped! :)