Duplicate value remove in array

$arr = array(1,2,3,3,4,5,5,6,7,8,8,6);
$second_array = array();
foreach($arr as $array_item){
foreach($second_array as $val){
if($array_item==$val){
continue 2;
}
}
$second_array[] = $array_item;
}
print_r($second_array);