生成自定义长度字符串

    def strGen(self, num):
        """
        生成可自定义长度的数字、字母和特殊字符混合的字符串
        :return:
        """
        list1 = [chr(i) for i in range(65, 91)] + [chr(i) for i in range(97, 123)] + [str(i) for i in range(10)] + ['.', '-', '~', '_']
        value = ""
        for i in range(num):
            value = value + list1[random.randint(0, len(list1) - 1)]
        return value