Comparing elements in a multidimensional array

Question

Say i have a multidimensional array. For example:

 Array ( 
         [0] => Array ( 
             [animal_id] => 5494 
             [animal_name] =>         


        

Answer 1

Array keys must be unique, so lets use that to our advantage.

function get_animal_key($animal) {
    return $animal['animal_type'] . '-' . $animal['animal_name'];
}

$uniques = array();
foreach ($array as $animal) {
    $key = get_animal_key($animal);
    $uniques[$key] = $animal;
}

var_export($uniques);

Gives the following array

array (
  'zebra-Suzy' => 
  array (
    'animal_id' => 5494,
    'animal_name' => 'Suzy',
    'animal_type' => 'zebra',
    'animal_location' => 0,
    'animal_awake' => 1,
    'animal_age' => 3,
  ),
  'panda-Joshua' => 
  array (
    'animal_id' => 5496,
    'animal_name' => 'Joshua',
    'animal_type' => 'panda',
    'animal_location' => 5,
    'animal_awake' => 0,
    'animal_age' => 8,
  ),
  'snake-Debra' => 
  array (
    'animal_id' => 5496,
    'animal_name' => 'Debra',
    'animal_type' => 'snake',
    'animal_location' => 7,
    'animal_awake' => 1,
    'animal_age' => 3,
  ),
  'zebra-Caleb' => 
  array (
    'animal_id' => 5495,
    'animal_name' => 'Caleb',
    'animal_type' => 'zebra',
    'animal_location' => 0,
    'animal_awake' => 1,
    'animal_age' => 3,
  ),
  'zebra-Emily' => 
  array (
    'animal_id' => 5496,
    'animal_name' => 'Emily',
    'animal_type' => 'zebra',
    'animal_location' => 0,
    'animal_awake' => 1,
    'animal_age' => 3,
  ),
)

As you can see, this takes the animal's type and name as the unique identifiers. Your question did not state what makes an animal unique, so alter the above to suit your needs.