Finding common value among sub-arrays in a multidimensional array

Question

I have the following array:

Array
(
    [0] => Array
        (
            [0] => 87
            [1] => 58
            [2] => 85
            [3]          


        

Answer 1

This works for me:

function multi_intersect($arr) {
   $return = array();
   foreach ($arr as $a) {
       foreach ($arr as $b) {
           if ($a === $b) continue;
           $return = array_merge($return, array_intersect($a, $b));
       }
   }
   return array_unique($return);
}

Should get you:

Array
(
    [0] => 58
)

The above will work if you have a common number in at least two of the sub-arrays.

After your edit:

You can simply use call_user_func_array on array_intersect, if you want to find numbers that are contained in all sub-arrays:

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