Question

这是我的两个def函数：

def valid_username(username):
     # implement the function here


    while True:

        try:
            username = input("Username: ")


            if len(username) < 8:
                print ("Sorry, the username must be at least 8 characters long.")


            if username.isalnum() == False:
                print ("Sorry, your name can only contain alpha numeric characters")


            numupper = 0


            for c in username:

                if c.isupper() == True:
                    numupper += 1

            if numupper > 0:
                print ("You have at least 1 uppercase in this username.")

            else:
                print ("You have no uppercase in this username.")

            numlower = 0

            for d in username:

                if d.islower() == True:
                    numlower +=1
            if numlower > 0:
                print ("You have at least 1 lowercase in this username.")

            else:
                print ("You have no lowercase in this username.")


            numdigit = 0

            for e in username:

                if e.isdigit() == True:
                    numdigit += 1
            if numdigit > 0:
                print ("You have at least one digit in this username.")

            else:
                print("You have no digits in this username.")

                continue

        except:
            print ("Sorry, not valid. Try again.")
        else:
            print ("Thank you for your input")
            break


def valid_password(password, username):
    # implement the function here

    while True:

        try:
            password = input("Password: ")

            if username in password:
                print ("That's not secure at all.")



            if len(password) < 8:
                print ("Sorry, the password must be at least 8 characters long.")


            if password.isalnum() == False:
                print ("Sorry, your password can only contain alpha numeric characters")


            numupper = 0


            for c in password:

                if c.isupper() == True:
                    numupper += 1

            if numupper > 0:
                print ("You have at least 1 uppercase in this password.")

            else:
                print ("You have no uppercase in this password.")

            numlower = 0

            for d in password:

                if d.islower() == True:
                    numlower +=1
            if numlower > 0:
                print ("You have at least 1 lowercase in this password.")

            else:
                print ("You have no lowercase in this password.")


            numdigit = 0

            for e in password:

                if e.isdigit() == True:
                    numdigit += 1
            if numdigit > 0:
                print ("You have at least one digit in this password.")

            else:
                print("You have no digits in this password.")

                continue

        except:
            print ("Sorry, not valid. Try again.")
        else:
            print ("Thank you for your input")
            break

我的主要计划是：

username = input("Username: ")


result, reason = uservalidation.valid_username(username)


if not(result):
    print (reason)


else:

    password = input("Password: ")


    pwresult, pwreason = uservalidation.valid_password(password, username)


    if not(pwresult):
        print (pwreason)
    else:
        print ("Username and Password combination is valid!")

当我运行它时，我得到以下内容：

Username: d
Username: user
Sorry, the username must be at least 8 characters long.
You have no uppercase in this username.
You have at least 1 lowercase in this username.
You have no digits in this username.
Username: craig2345
You have no uppercase in this username.
You have at least 1 lowercase in this username.
You have at least one digit in this username.
Thank you for your input
Traceback (most recent call last):
  File "C:/Users/Si Hong/Desktop/pythontest/HuangSiHong_Assign8_part3.py", line 7, in <module>
    result, reason = uservalidation.valid_username(username)
TypeError: 'NoneType' object is not iterable
>>>

我无法弄清楚为什么当我输入用户名的第一个值时，它不会触发该功能，但是在我第二次进入该功能后进行，并且我也是不确定如何解决非类型错误问题，如果有人可以向我解释，那将非常感谢你！

Answer 1

如果函数没有显式返回值，则它会隐式返回None，这不能应用于以这种方式解包的元组。

Answer 2

您看到Username:提示两次的原因是您要求在主程序中输入一次，然后立即再次在函数内部输入。该函数不应该询问用户任何输入，它从传递给它的参数中获取用户名的值。

你看到关于NoneType的错误（不是你写的非类型，Python是区分大小写的，你应该养成完全按照它所说的那样的习惯）的原因是你的函数valid_password（）确实完成了返回语句返回程序所期望的两个值。实际上，它根本没有return语句，这意味着它有效地返回特殊的Python值None（这是NoneType类型的对象）。

因为您告诉程序从函数返回的任何内容中提取两个值，所以它试图通过迭代对返回的值进行操作。 NoneType不是可以迭代的类型之一（因为它不包含任何信息），因此是错误消息。

非类型问题以及用户名变量问题

2 个答案: