up vote 3 down vote favorite

Is there a better way than using array-walk in combination with unserialize?

I have two arrays which contain objects. The objects can be same or can be different. I want to merge both arrays and keep only unique objects.

This seems to me like a very long solution for something so trivial. Is there any other way?

class Dummy
{
    private $name;
    public function __construct($theName) {$this->name=$theName;}
}

$arr = array();
$arr[] = new Dummy('Dummy 1');
$arr[] = new Dummy('Dummy 2');
$arr[] = new Dummy('Dummy 3');

$arr2 = array();
$arr2[] = new Dummy('Dummy 1');
$arr2[] = new Dummy('Dummy 2');
$arr2[] = new Dummy('Dummy 3');

function serializeArrayWalk(&$item)
{
    $item = serialize($item);
}

function unSerializeArrayWalk(&$item)
{
    $item = unserialize($item);
}

$finalArr = array_merge($arr, $arr2);
array_walk($finalArr, 'serializeArrayWalk');
$finalArr = array_unique($finalArr);
array_walk($finalArr, 'unSerializeArrayWalk');

var_dump($finalArr);
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95% accept rate
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2 Answers

up vote 1 down vote accepted

From here: http://php.net/manual/en/function.array-unique.php#75307

This one would work with objects and arrays also.

<?php
function my_array_unique($array, $keep_key_assoc = false)
{
    $duplicate_keys = array();
    $tmp         = array();       

    foreach ($array as $key=>$val)
    {
        // convert objects to arrays, in_array() does not support objects
        if (is_object($val))
            $val = (array)$val;

        if (!in_array($val, $tmp))
            $tmp[] = $val;
        else
            $duplicate_keys[] = $key;
    }

    foreach ($duplicate_keys as $key)
        unset($array[$key]);

    return $keep_key_assoc ? $array : array_values($array);
}
?>
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Thank you very much. – Richard Knop Dec 22 '10 at 9:12
@Richard Knop, you are welcome, good luck! – Silver Light Dec 22 '10 at 10:05
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up vote 3 down vote

I know there's already an accepted answer, but here's an alternative.

Contrary to the previous answer, it uses in_array() since the nature of comparing objects in PHP 5 allows us to do so. Making use of this object comparison behaviour requires that the array only contain objects, but that appears to be the case here.

$merged = array_merge($arr, $arr2);
$final  = array();

foreach ($merged as $current) {
    if ( ! in_array($current, $final)) {
        $final[] = $current;
    }
}

var_dump($final);
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Works nice, it might be faster than the other one (dont really know) but i will use yours because i dont have to take make an extra function for it :D – Gigala 2 days ago
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