php - 比较和提取常见的数组元素

Question

I have been trying to compare values of inner arrays from a multidimensional array and extract those common values into another array. I have tried using array_intersect along with a foreach loop but this is not giving me result, here the number of inner arrays is dynamic and generated from a different function. Have anyone tried before comparing array elements of a multidimensional array?

My Array:

    $days_filter = array(
    [0] => array(
        '00:00',
        '01:30',
        '02:30',
    ),
    [1] => array(
        '00:00',
        '01:30',
        '03:30',
    ),
    [2] => array(
        '00:30',
        '01:30',
        '02:30',
    ),
    [3] => array(
        '00:30',
        '01:30',
        '04:30',
    ),
);

$res_arr = $days_filter[0];
foreach ($days_filter as $filter) {
    $res_arr = array_intersect($res_arr, $filter);
}

Expected output array:

$res_arr = array(
    [0]=>'01:30'
)

because 01:30 is the common element of all inner arrays.

Answer 1

array_intersect() works for you..

$days_filter = array(
    0 => array(
        '00:00',
        '01:30',
        '02:30',
    ),
    1 => array(
        '00:00',
        '01:30',
        '03:30',
    ),
    2 => array(
        '00:30',
        '01:30',
        '02:30',
    ),
    3 => array(
        '00:30',
        '01:30',
        '04:30',
    ),
);
$first = $days_filter[0];

for($i=1; $i<count($days_filter); $i++)
{
  $result = array_intersect($first, $days_filter[$i]);
  $first = $result;
}

print_r($result);

This will give you :

Array
(
    [1] => 01:30
)