(PHP 4, PHP 5, PHP 7)
array_unshift — Prepend one or more elements to the beginning of an array
   array_unshift() prepends passed elements to the front
   of the array. Note that the list of elements is
   prepended as a whole, so that the prepended elements stay in the same
   order.  All numerical array keys will be modified to start counting from
   zero while literal keys won't be touched.
  
arrayThe input array.
value1First value to prepend.
   Returns the new number of elements in the array.
  
Example #1 array_unshift() example
<?php
$queue = array("orange", "banana");
array_unshift($queue, "apple", "raspberry");
print_r($queue);
?>
The above example will output:
Array
(
    [0] => apple
    [1] => raspberry
    [2] => orange
    [3] => banana
)