PHP Manual: Adds values to the front of the deque

public void Ds\Deque::unshift(mixed $values = ?)

Adds values to the front of the deque, moving all the current values forward to make room for the new values.

values

The values to add to the front of the deque.

Note:
Multiple values will be added in the same order that they are passed.

No value is returned.

Example #1 Ds\Deque::unshift example

<?php
$deque = new \Ds\Deque([1, 2, 3]);

$deque->unshift("a");
$deque->unshift("b", "c");

print_r($deque);
?>

The above example will output something similar to:

Ds\Deque Object
(
    [0] => b
    [1] => c
    [2] => a
    [3] => 1
    [4] => 2
    [5] => 3
)