How to modify an array

      
      $names = array('Mike', 'Mike', 'Mike', 'Anne', 'Joel', 'Joel');
      $names = array_unique($names); // Mike, Anne, Joel
      $names = array_reverse($names); // Joel, Anne, Mike
      shuffle($names); // Mike, Joel, Anne (for example)

How to modify an associative array

      
      $tax_rates = array('NC' => 7.75, 'NY' => 8.875, 'CA' => 8.25);

      $tax_rates = array_reverse($tax_rates, true);

How to get random keys from an array

      
      $names = array('Mike', 'Anne', 'Joel', 'Ray', 'Pren');

      $key = array_rand($names); // 2 (for example)

      $names_rand = array_rand($names, 3); // 0, 1, 3 (for exmple)

How to shuffle and deal a deck of cards

      // Create the deck of cards 

      $faces = array('2', '3', '4', '5', '6', '7', '8', '9', 'T', 'J', 'Q', 'K', 'A');
 $suits = array('h', 'd', 'c', 's');

      $cards = array();

      foreach($faces as $face) {

          foreach($suits as $suit) {

            $cards[] = $face . $suit; 

          }

      }

      // Shuffle the deck and deal the cards

      shuffle($cards);

      $hand = array();

      for ($i = 0; $i < 5; $i++) {

        $hand[] = array_pop($cards);

      }

      echo implode(',', $hand); // 9c,6d,Ks,4c,7h (for example)
      Hand = 6c,2h,2s,Kh,Qd

The sorting functions don’t return an array. Instead, they modify the array that’s passed to them.
The $compare parameter works the same for all sorting functions.A stack is a special type of array that implements a last-in, first-out (LIFO) collec-tion of values. You can use the array_push() and array_pop() functions to add and remove elements in a stack.

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