This removeAdd function, the first argument shift your array then unshif the second argument to your array. first argument is an array and second argument can be int or str.
<?php
function removeAdd ($arr, $newer){
 $a = array_shift($arr);
 $b = array_unshift($arr, $newer);
 foreach ($arr as $value){
 echo $value."<br />";
 }
}
$a = array(1,2,3,4,5,6);
foreach ($a as $current){
 echo $current."<br />";
}
echo "<hr />";
removeAdd($a, 0);
?>

OUTPUT:
1
2
3
4
5
6
_______
0
2
3
4
5
6