How to randomize, return and remove numbers from a pool using PHP

$random_numbers = range(1,100);
shuffle($random_numbers);
$numbers_chosen = array($random_numbers[0],$random_numbers[1],
$random_numbers[2],$random_numbers[3]);

print "before ";
print_r($random_numbers); // first four numbers chosen

$random_numbers = array_splice($random_numbers,4);

print "

---

after ";
print_r($random_numbers); // first four numbers chosen

print "

---

chosen ";
print_r($numbers_chosen); // first four num5 bers chosen
?>