add element in a particular position in an array

<?php
$input = array("red", "green", "blue", "yellow");
$input1 = array_slice($input,2);
$input2 = array_splice($input,2);
array_push($input1, "apple", "raspberry");
$input3=array_merge($input1,$input2);
//print_r($input3);

$input = array("red", "green", "blue", "yellow");
array_splice($input, 2, 0, "purple");
print_r($input);
?>