Array filter with Implode process - PHP

 Array filter with Implode process :

<?php
$chat_list=array(0,1,2,3,4,5,0,4,2,3);  // This array have duplicates

$user=array();

foreach($chat_list as $key=>$chat)
{
 $user[$key]=$chat['UserName'];
}

 print_r(implode(' , ',array_unique($user))); //This will show unique and added comma for each element.

 ?>