Question

所以我在搞弄Python。我想不出怎么做，所以如果您输入无效的用户名/密码，那么它将返回循环的顶部并再次从if语句开始。当我输入无效的用户名或密码时，它不会这样做。所以请有人帮我解释一下为什么？

values = ["User1", "123", "User2", "321", "User3", "132"]

print("Please log in to the program")
username = input("Please enter your username: ")
attempts = 3
while attempts >=1:
    if username in values:
        place = values.index(username)
        passposition = int(place + 1)
        print("Your username is valid.")
        password = input("Now please enter the password to your account. Once again, passwords are case sensitive: ")
        if password == values[passposition]:
            print("The password is correct, welcome to the program")
        else:
            print("The password was invalid, please try again")
            attempts -= 1
            print("You now have ", attempts, " more attempts to log in with a valid username and password")
    else:
        print("Your username is invalid, please try again")

尝试-= 1 print（“您现在有尝试，使用有效用户名和密码登录的更多尝试”）

Answer 1

这对您有用吗？

values = ["User1", "123", "User2", "321", "User3", "132"]
attempts = 3
print("Please log in to the program")
while attempts >=1:
    #You need to ask for the username again, if you don't do this the variable is always assigned with a invalid value
    #That's why it must be inside the loop
    username = input("Please enter your username: ")
    if username in values:
        place = values.index(username)
        passposition = int(place + 1)
        print("Your username is valid.")
        password = input("Now please enter the password to your account. Once again, passwords are case sensitive: ")
        if password == values[passposition]:
            print("The password is correct, welcome to the program")
            #Once you have the right credentials you need to break the loop, if you comment the break you'll see that the programs asks again for the password
            break
        else:
            print("The password was invalid, please try again")
            attempts -= 1
            print("You now have ", attempts, " more attempts to log in with a valid username and password")
    else:
        print("Your username is invalid, please try again")
        attempts -= 1
        print("You now have ", attempts, " more attempts to log in with a valid username and password")

返回if语句的顶部[Python]

1 个答案: