<?php
// define nested array
$data = array("United States",array("Texas", "Philadelphia"),array("California",array ("Los Angeles", "San Francisco")));
// initialize an Iterator
// pass it the array to be processed
$iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($data));
// iterate over the array
// result: "UNITED STATES TEXAS PHILADELPHIA CALIFORNIA LOS ANGELES SAN FRANCISCO"
foreach ($iterator as $value) {
print strtoupper($value) . " <br>";
}