<?php $array = array('foo', 'bar', 'baz'); $iterator = new ArrayIterator($array); $regexIterator = new RegexIterator($iterator, "/f/", null, RegexIterator::USE_KEY); var_dump($regexIterator->getFlags() === RegexIterator::USE_KEY); // Test a change in flags, there's only one class constant so it has to be another int value $regexIterator->setFlags(3); var_dump($regexIterator->getFlags() === RegexIterator::USE_KEY); $regexIterator->setFlags(RegexIterator::USE_KEY); var_dump($regexIterator->getFlags() === RegexIterator::USE_KEY);