yii\helpers\BaseStringHelper::basename PHP Method

    public static function basename($path, $suffix = '')
    {
        if (($len = mb_strlen($suffix)) > 0 && mb_substr($path, -$len) === $suffix) {
            $path = mb_substr($path, 0, -$len);
        }
        $path = rtrim(str_replace('\\', '/', $path), '/\\');
        if (($pos = mb_strrpos($path, '/')) !== false) {
            return mb_substr($path, $pos + 1);
        }
        return $path;
    }