- print_r: documentation ( source)
- array_unique: documentation ( source)
<?php
class A {};
$a = new A();
class B {};
$b = new B();
$array = array();
for($i=0; $i<28; $i++)
$array[$i] = $a;
$array[0] = $array[26] = $b;
$array = array_unique($array,SORT_REGULAR);
print_r($array);