$arr = array('a', 'a', 'c', 'd', 'b', 'f', 'b');
$new_arr = array();
$x = 0;
$i = count($arr);
for($o=0; $o<$i; $o++){
$is_in = false;
for($n=0; $n < $x; $n++){
if($arr[$o] == $new_arr[$n]){
$is_in = true;
break;
};
}
if($is_in == false){
$new_arr[$x] = $arr[$o];
$x++;
}
}
print_r($new_arr);