php - How to return duplicate values from multidimentional array in PHP if the value exists in all arrays.

Question

Ive been trying to figure this out for some days now without good results. I have this multidimentional array of objects in PHP (print_r):

Array
(
[3] => Array
    (
        [0] => stdClass Object
            (
                [productoId] => 16
            )

        [1] => stdClass Object
            (
                [productoId] => 21
            )

        [2] => stdClass Object
            (
                [productoId] => 22
            )

    )

[7] => Array
    (
        [0] => stdClass Object
            (
                [productoId] => 16
            )

        [1] => stdClass Object
            (
                [productoId] => 21
            )

        [2] => stdClass Object
            (
                [productoId] => 22
            )

    )

[6] => Array
    (
        [0] => stdClass Object
            (
                [productoId] => 16
            )

        [1] => stdClass Object
            (
                [productoId] => 17
            )

    )

)

I would like to get the duplicate values that exist in all the arrays, example:

stdClass Object
        (
            [productoId] => 16
        )

But not:

stdClass Object
        (
            [productoId] => 21
        )

Any idea how I can achieve this?

Answer 1

like this:

$array = array(
            3 => array((object) array('productoId' => '16'), (object) array('productoId' => '21'), (object) array('productoId' => '22')),
            7 => array((object) array('productoId' => '16'), (object) array('productoId' => '21'), (object) array('productoId' => '22')),
            6 => array((object) array('productoId' => '16'), (object) array('productoId' => '17'))
        );

$arrays = count($array);
$match = array();
$duplicates = array();
foreach($array as $one){
    foreach($one as $single){
        $var = (array)$single;
        if(!isset($match[$var['productoId']])) { $match[$var['productoId']] = 0; }
        $match[$var['productoId']]++;
        if($match[$var['productoId']] == $arrays){
            $duplicates[] = (int)$var['productoId'];
        }
    }
}
print_r($duplicates);