PHP Random Shuffle Array Maintaining Key => Value

Question

I've been looking on google for the answer but can't seem to find something fool-proof and cant really afford to mess this up (going live into a production site).

What I have is an advanced search with 20+ filters, which returns an array including an ID and a Distance. What I need to do is shuffle these results to display in a random order every time. The array I have that comes out at the moment is:

Array (
    [0] => Array ( [id] => 1 [distance] => 1.95124994507577 )
    [1] => Array ( [id] => 13 [distance] => 4.75358968511882 )
    [2] => Array ( [id] => 7 [distance] => 33.2223233233323 )
    [3] => Array ( [id] => 21 [distance] => 18.2155453552336 )
    [4] => Array ( [id] => 102 [distance] = 221.2212587899658 )
)

What I need to be able to do is randomise or order of these every time but maintain the id and distance pairs, i.e.:

Array (
    [4] => Array ( [id] => 102 [distance] = 221.2212587899658 )
    [1] => Array ( [id] => 13 [distance] => 4.75358968511882 )
    [3] => Array ( [id] => 21 [distance] => 18.2155453552336 )
    [2] => Array ( [id] => 7 [distance] => 33.2223233233323 )
    [0] => Array ( [id] => 1 [distance] => 1.95124994507577 )
)

Thanks :)

Answer 1

The first user post under the shuffle documentation:

Shuffle associative and non-associative array while preserving key, value pairs. Also returns the shuffled array instead of shuffling it in place.

function shuffle_assoc($list) { 
  if (!is_array($list)) return $list; 

  $keys = array_keys($list); 
  shuffle($keys); 
  $random = array(); 
  foreach ($keys as $key) { 
    $random[$key] = $list[$key]; 
  }
  return $random; 
} 

Test case:

$arr = array();
$arr[] = array('id' => 5, 'foo' => 'hello');
$arr[] = array('id' => 7, 'foo' => 'byebye');
$arr[] = array('id' => 9, 'foo' => 'foo');
print_r(shuffle_assoc($arr));
print_r(shuffle_assoc($arr));
print_r(shuffle_assoc($arr));

Answer 2

As of 5.3.0 you could do:

uksort($array, function() { return rand() > rand(); });

Answer 3

Take a look to this function here :

     $foo = array('A','B','C'); 


function shuffle_with_keys(&$array) {
    /* Auxiliary array to hold the new order */
    $aux = array();
    /* We work with an array of the keys */
    $keys = array_keys($array);
    /* We shuffle the keys */`enter code here`
    shuffle($keys);
    /* We iterate thru' the new order of the keys */
    foreach($keys as $key) {
      /* We insert the key, value pair in its new order */
      $aux[$key] = $array[$key];
      /* We remove the element from the old array to save memory */
      unset($array[$key]);
    }
    /* The auxiliary array with the new order overwrites the old variable */
    $array = $aux;
  }

      shuffle_with_keys($foo);
      var_dump($foo);

Original post here : http://us3.php.net/manual/en/function.shuffle.php#83007