How random is PHP's shuffle function?

Question

Does anyone know what\'s the randomness of PHP\'s shuffle() function? Does it depend on the operating system? Does it use PHP\'s own seeder?

Is it poss

Answer 1

Works with associative and numeric arrays:

function mt_shuffle_array($array) {
    $shuffled_array = [];
    $arr_length = count($array);

    if($arr_length < 2) {
        return $array;
    }

    while($arr_length) {
        --$arr_length;
        $rand_key = array_keys($array)[mt_rand(0, $arr_length)];

        $shuffled_array[$rand_key] = $array[$rand_key];
        unset($array[$rand_key]);
    }

    return $shuffled_array;
}

$array = [-2, -1, 'a' => '1', 'b' => '2', 'c' => '3', 11, 'd' => '4', 22];
$shuffled_array = mt_shuffle_array($array);