$re = '/<span.*?data-snippet-php="(.*?)".*?>.*?<\/span>/m';
$str = 'HTML Code<br><span class="block" title="Label: Titel" data-snippet-php="<?php _e(\'Titel\',\'grid_test\') ?>" editable="false">[ Titel ]</span>: <span class="block" title="Datenfeld: Titel" data-snippet-bind="#: post_title #" editable="false">{ post_title }</span> text text text <span class="block" title="Label: Desc" data-snippet-php="<?php _e(\'Desc\',\'grid_test\') ?>" editable="false">[ Desc ]</span>: text text text';
$subst = "$1";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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