Question

我正在尝试为自己编写登录和注册脚本，但是我的用户名定义存在问题。我可以在没有任何一种验证方法的情况下运行该代码，但是有了它，代码似乎总是坏了。

    usernameloop = 1
    while usernameloop == 1:
        username = input("Please input your desired username.")
        if len(username) >> 20:
            print("Unable to choose that username, you need to have less than 20 characters in your username.")
        elif len(username) >= 4 and len(username) <= 20:
            print("Username Selected. Your username is:", username)
            time.sleep(1)
            usernameloop = 0
            break

# This is the problematic statement. It doesn't work if this is in and always goes to this statement even if the validation should be correct.

        elif len(username) << 4: 
            print("Unable to choose that username, you need 3 or more characters in your username.")
        else:
            print("An Unknown Error Occurred, contact x with the screenshot of the conversation history.")
            time.sleep(10)
            exit()

有人知道为什么它不起作用吗，我不知道为什么它不起作用。

Answer 1

使用单个“ <”或“>”代替“ <<”或“ >>”，没关系。

Answer 2

>是Comparison Operators

>>是bitwise oprator

if，elif和len（x）的问题

2 个答案: