Comparing elements in a multidimensional array

问题

Say i have a multidimensional array. For example:

And i want to compare all the snakes against the snakes, and all the panda's against the panda's etc (but not a snake against a panda) and put the unique elements into an array(all unique elements into a single array), how would i go about doing this. Since they are elements within an array, i'm a bit stumped. Also, i won't know in advance how many different types there will be. For instance, one time i could be passed an multidimensional array with Panda, Bear, Snake -- Next time i could be passed an array with Bird, Cat, Panda, Zebra.

Any ideas?

FINAL OUTPUT

      Array ( 
     [0] => Array ( 
         [animal_id] => 5494 
         [animal_name] => "Suzy"
         [animal_type] => "zebra" 
         [animal_location] => 0 
         [animal_awake] => 1
         [animal_age] => 3 ) 
     [1] => Array ( 
         [animal_id] => 5494 
         [animal_name] => "Joshua"
         [animal_type] => "panda"
         [animal_location] => 5
         [animal_awake] => 0
         [animal_age] => 8 )
    [2] => Array ( 
         [animal_id] => 5495 
         [animal_name] => "Caleb"
         [animal_type] =>  "zebra"
         [animal_location] => 0
         [animal_awake] => 1
         [animal_age] => 3 )    
    [3] => Array ( 
         [animal_id] => 5495 
         [animal_name] => "Debra"
         [animal_type] =>  "snake"
         [animal_location] => 7 
         [animal_awake] => 1
         [animal_age] => 3 ) 
    [4] => Array ( 
         [animal_id] => 5496 
         [animal_name] => "Emily"
         [animal_type] =>  "zebra"
         [animal_location] => 0
         [animal_awake] => 1
         [animal_age] => 3 )    

     )

回答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.

回答2:

How about sorting them by type:

$animalsByType = array();
foreach ($array as $animal) {
    $type = $animal['animal_type'];
    if (!isset($animalsByType[$type])) {
        $animalsByType[$type] = array();
    }
    $animalsByType[$type][] = $animal;
}

I'm not sure what kind of comparing you want to do, but this at least gets you individual sublists by type.

回答3:

You could run through the array and then crosscheck every item:

foreach($aAnimals AS $iKey => $aAnimalData
{
    foreach($aAnimals AS $iSubKey => $aData)
    {
        if($aAnimalData['animal_type'] == $aData['animal_type'] && $iKey != $iSubKey)
        {
            // Start doing whatever you want to do when the types match.
            // The last part makes sure the second foreach does not 
            // match with the first one.
        }
    }
}

If you specify what kind of comparing you want I could improve this answer with that.

来源：https://stackoverflow.com/questions/12030334/comparing-elements-in-a-multidimensional-array

标签

php

multidimensional-array