php arrays finding the elements present in all sub-arrays

Question

I have a php multidimensional array (2 levels) with some values and I want to identify what values are present in all arrays.

Array
(
    [1] => Array
        (
            [0] => 1
            [1] => 3
        )

    [2] => Array
        (
            [0] => 1
            [1] => 2
        )

    [3] => Array
        (
            [0] => 1
            [1] => 3
        )

)

....in our case value 1 is present in all 2nd level arrays. Is there a way to identify that?

Answer 1

You can use array_intersect to do an intersection of all arrays:

$intersection = $arr[0];
for ($i=1, $n=count($arr); $i<$n; ++$i) {
    $intersection = array_intersect($intersection, $arr[$i]);
    if (empty($intersection)) break;
}

Or a little shorter using call_user_func_array:

$intersection = call_user_func_array('array_intersect', $arr);