framework/validators/IpValidator.php
private function parseNegatedRange($string)
    {
        $isNegated = strpos($string, static::NEGATION_CHAR) === 0;
        return [$isNegated, $isNegated ? substr($string, strlen(static::NEGATION_CHAR)) : $string];
    }
private function parseNegatedRange($string)
    {
        $isNegated = strpos($string, static::NEGATION_CHAR) === 0;
        return [$isNegated, $isNegated ? substr($string, strlen(static::NEGATION_CHAR)) : $string];
    }
Parses IP address/range for the negation with [[NEGATION_CHAR]].

@param $string
@return array `[0 => bool, 1 => string]`
- boolean: whether the string is negated
- string: the string without negation (when the negation were present)