$values Values * * @return array * * @since 1.0.0 */ public static function frequency(array $values) : array { $frequency = []; $sum = 1; if (!(\is_array(\reset($values)))) { $sum = \array_sum($values); } foreach ($values as $value) { $frequency[] = \is_array($value) ? self::frequency($value) : $value / $sum; } return $frequency; } }