Combining php function

Combining php function

This code works:
$host =
parse_url('http://www.cc.joomla.xc.my/paypal.com/myspace.com/login.php',
PHP_URL_HOST);
$host_names = explode(".", $host);
print_r($host_names);
echo "<br>";
$l = array_slice($host_names, -3);
print_r($l);
echo "<br>";
$subdomain = implode(".", $l);
echo $subdomain; //final result

Is it possible to combine function in one line for example like this:
$host_names = implode(array_slice (explode(".", $host)($host_names,
-3)(".", $l);
The example above does not worked. I think I have seen it before where you
can combine function.
Thanks in advance for any help.