$re = '/(<table.*?class="(.+?)".*?>.+?<td>(.+?)<\/td>.+?.+?<\/table>)/is';
$str = '<table class="grid grid-2">
<tbody>
<tr>
<td>
<p class="large-text">test</p>
</td>
<td>
<p class="large-text">test</p>
</td>
</tr>
</tbody>
</table>
<p> </p>
<table class="grid grid-3">
<tbody>
<tr>
<td>
<p style="text-align: center;">test</p>
</td>
<td>
<p style="text-align: center;">test</p>
</td>
<td>
<p style="text-align: center;">test</p>
</td>
</tr>
</tbody>
</table>
<p> </p>
<table class="grid grid-3">
<tbody>
<tr>
<td class="large-text"> test</td>
<td></td>
<td></td>
</tr>
</tbody>
</table>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php