Removing duplicate entries in an array- Undefined offset error(PHP) -

i new php , trying remove duplicate entries in array. end desired output, getting 2 "undefined offset" errors along way. code have: $this->master refers array declared in beginning of class.

    public function removeduplicates(){         $var = count($this->master);             for($i = 0; $i < $var; $i++){                     for($j = 0; $j <$var; $j++){                         if(($this->master[$i] == $this->master[$j]) && $i != $j){                                                        $this->shiftleft($j, $var);                             $var --;                         }                     }             }     }      public function shiftleft($t, $s){         while($t < $s){             echo "$t ";             $this->master[$t] = $this->master[$t+1];             $t++;         }         unset($this->master[$t-1]);     } 

it simple logical error cannot seem find where. appreciated.

see if works

 $unique = array_unique($this->master);