- var_dump: documentation ( source)
<?php
$arrayIterator = new ArrayIterator(array('test 1' => ['derp'], 'another test', 'test 123'));
$regexIterator = new RegexIterator($arrayIterator, '/^test/', RegexIterator::REPLACE, RegexIterator::USE_KEY);
$regexIterator->replacement = '';
foreach ($regexIterator as $value) {
var_dump($value);
echo "\n";
}