即使我成功登录，它仍会打印字符串“用户不正确”。我该如何阻止这种情况发生？ [英] Even when I successfully login it still prints the string "user incorrect" how do I stop this from happening?

问题描述

# Test Login 

userlist = {"user" : "password", "user2" : "password2"}

login = input('do you have an account (Y/N)?')
if (login == 'n'):
    New_User = input('create user: ')
    New_Pass = input('create password: ')
    userlist[New_User] = New_Pass

loop = 'true'
while (loop == 'true'):
    username = input("Please enter your username: ")
    for x in userlist:
        if (username == x):
            password = input("Please enter your password: ")
            if (password == userlist[x]):
                print ("Logged in successfully as " + username)
                loop = 'false'
            else:
                print ("Password incorrect!")
        else: 
            print ("User incorrect")

什么我试过了：

What I have tried:

# Test Login 

userlist = {"user" : "password", "user2" : "password2"}

login = input('do you have an account (Y/N)?')
if (login == 'n'):
    New_User = input('create user: ')
    New_Pass = input('create password: ')
    userlist[New_User] = New_Pass

loop = 'true'
while (loop == 'true'):
    username = input("Please enter your username: ")
    for x in userlist:
        if (username == x):
            password = input("Please enter your password: ")
            if (password == userlist[x]):
                print ("Logged in successfully as " + username)
                loop = 'false'
            else:
                print ("Password incorrect!")
    else: 
        print ("User incorrect")

推荐答案

出于debuf目的，将代码更改为：

For debuf purpose, change your code to:

userlist = {"user" : "password", "user2" : "password2", "user3" : "password3", "user4" : "password4", "user5" : "password5"}

和：

and:

print ("User incorrect "+x)

并运行代码。



您将看到每条消息都打印出来输入的时间不是您检查的用户名。问题在于你的逻辑，你知道只有在检查了列表中的每个用户名并且没有匹配后用户才是错误的。

你需要做什么：

and run the code.

You will see that the message is printed every time the input is not the username you check. The problem is your logic, you know the user is incorrect only once you have checked against every usernames in your list and that there was no match.
What you have to do:

loop in userlist
  check for a match with input
if there was no match
  user is inxorrect

有一个工具可以让你看到你的代码在做什么，它的名字是调试的。它也是一个很好的学习工具，因为它向你展示了现实，你可以看到哪种期望与现实相符。

当你不明白你的代码在做什么或为什么它做它做的时候，答案就是答案是调试器。

使用调试器查看代码正在执行的操作。只需设置断点并查看代码执行情况，调试器允许您逐行执行第1行并在执行时检查变量。



调试器 - 维基百科，免费的百科全书 [ ^ ]

27.3。 pdb - Python调试器 - Python 3.6.1文档 [ ^ ]

使用Python进行调试Python征服宇宙 [ ^ ]

pdb - 交互式调试器 - 本周的Python模块 [ ^ ]

调试器在这里显示你的内容代码正在做，你的任务是与它应该做的事情进行比较。

调试器中没有魔法，它没有发现错误，它只是帮助你。当代码没有达到预期的效果时，你就会接近一个错误。

There is a tool that allow you to see what your code is doing, its name is debugger. It is also a great learning tool because it show you reality and you can see which expectation match reality.
When you don't understand what your code is doing or why it does what it does, the answer is debugger.
Use the debugger to see what your code is doing. Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.

Debugger - Wikipedia, the free encyclopedia[^]
27.3. pdb — The Python Debugger — Python 3.6.1 documentation[^]
Debugging in Python | Python Conquers The Universe[^]
pdb – Interactive Debugger - Python Module of the Week[^]
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't find bugs, it just help you to. When the code don't do what is expected, you are close to a bug.

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