public function map_string($pcre = null)
	{
		$list = array_map('strval', $this->getArrayCopy());
		$dlist = array();

		if ($pcre)
		{
			foreach ($list as $item)
			{
				$dlist[] = preg_match($pcre, $item) ? $item : null;
			}

			$list = array_values(array_filter($dlist));
		}

		return $list;
	}