- iterator_to_array: documentation ( source)
<?php
$html = <<<HTML
<!DOCTYPE HTML>
<html>
<body>
<p><span class="unwrap_me">Lorem</span><span class="unwrap_me">ipsum</span><span class="unwrap_me">dolor</span></p>
</body>
</html>
HTML;
$dom = new DOMDocument();
$dom->loadHTML($html);
$spans = iterator_to_array($dom->getElementsByTagName('span')->getIterator());
foreach ($spans as $span) {
if ('unwrap_me' === $span->getAttribute('class')) {
$span->replaceWith(...$span->childNodes);
}
}