Добавить элемент в середину массива

$input = array("red", "green", "blue", "yellow");
array_splice($input, 3, 0, "purple");
// $input is now array("red", "green",
//          "blue", "purple", "yellow");

$input = array("red", "green", "blue", "yellow");
array_splice($input, 3, 0, array("purple", "black"));
// $input is now array("red", "green",
//          "blue", "purple", "black", "yellow");