I have in array 6 values, I need to return 4 random values from an array, but all shouldn't be equal.

Example:

If I have an array (6 values) 1, 2, 3, 4, 5, 6 I need to get 4 random values from it for example 3, 1, 4, 2. For now It returning for example: 2,2,3,2

Here is code:

$array= array(1, 2, 3, 4, 5, 6);
for ($i = 0; $i < 4; $i++) {
$k = array_rand($array);
$random_element = $array[$k];
echo $random_element;
}