function charfilter($string, $excluding, $charset)
{
	$cs = is_array($charset);
	$excluding === true ? return str_replace(!$cs ? str_split($charset) : $charset, '', $string) : 0;
	$result = '';
	$sl = strlen($string);
	$cs ? $charset = implode('', $charset) : 0;
	for ($i = 0; $i < $sl; ++$i)
	{
		strpos($charset, $string[$i]) ? $result .= $string[$i] : 0;
	}
	return $result;
}