I have a program which gives out 10 random cards from a normal deck (and doesn't put them back in).  

Sometimes when I run the script in the shell I recieve the following error message: 

> 
> PHP Notice: Undefined offset: ..... on line 15
> 
> 
> 

My code looks as follows:

```
<?php
  $deck = array(
      array('A', 2, 3, 4, 5, 6, 7, 8, 9, 10, 'J', 'Q', 'K'), //club
      array('A', 2, 3, 4, 5, 6, 7, 8, 9, 10, 'J', 'Q', 'K'), //spade
      array('A', 2, 3, 4, 5, 6, 7, 8, 9, 10, 'J', 'Q', 'K'), //heart
      array('A', 2, 3, 4, 5, 6, 7, 8, 9, 10, 'J', 'Q', 'K')  //diamond
  );

  $i = 0;
  for ($i = 1; $i <= 10; $i++) {
      $a = rand(0, 3);        //card's suit
      $nr = count($deck[$a]); //how many cards of the suit are available?
      $b = rand(0, $nr--);    //pick a random number out of the available ones
      $card = $deck[$a][$b];  //pick a card [---LINE 15---]

      switch ($a) {
          case 0:
              $c = "club";
              break;
          case 1:
              $c = "spade";
              break;
          case 2:
              $c = "heart";
              break;
          case 3:
              $c = "diamond";
              break;
      }

      echo $c . " " . $card . "\n" . "remaining: " . $nr . "\n";

      unset($deck[$a][$b]);    //remove the card you drew
      array_values($deck[$a]); //rearrange the index of the suit you drew the card from
  }
?>

```

Could someone help a newbie out?