使用文本文件创建 Python 登录系统

Question

我正在尝试使用文本文件在 python 中创建一个基本的注册和登录系统。我还希望程序一次性运行，这意味着我希望用户能够注册，然后立即继续登录，而不是让他们返回并再次运行代码.但是，我编写的代码由于某种原因无法做到这一点。我在注册函数的末尾添加了“signin()”，以允许用户在成功注册后继续登录，但这样做会引发错误。相反，我必须再次运行代码才能识别新注册。

代码如下：

def signin():
    q = 0
    user = input('Username: ')
    password = input('Password: ')
    with open('username.txt', mode='r')as names:
        for i in names:
            foundname = names.readlines()
    with open('password.txt', mode='r')as passwords:
        for j in passwords:
            foundpass = passwords.readlines()
    if user + "\n" in foundname:  # ReadLines() adds newlines
        user_num = foundname.index(user + "\n")
        for i in range (0,user_num):
            if password + "\n" == foundpass[i]:
                print("Login Successful.")
        print("Incorrect Password. Try Again.")
        signin()

    else:
        print("Username not found. Try again")
        signin()

def signup():
    with open('username.txt', mode='a')as names:
        print("Please provide the following details to sign up")
        name = str(input("Username: "))
        names.write(f"{name}\n")
    with open('password.txt', mode='a')as passwords:
        password = (input("Password: "))
        passwords.write(f'{password}\n')
        print("signup successful. You can sign-In Now.")
        signin()
signup()

这是我不断收到的输出和错误：

Please provide the following details to sign up
Username: abcdef
Password: password1
signup successful. You can sign-In Now.
Username: abcdef
Password: password1
Traceback (most recent call last):
  File "D:/student.py", line 34, in <module>
    signup()
  File "D:/student.py", line 33, in signup
    signin()
  File "D:student.py", line 14, in signin
    if password + "\n" == foundpass[i]:
IndexError: list index out of range

Process finished with exit code 1

但是当我再次运行代码时，我上次注册时使用的凭据似乎有效。

Please provide the following details to sign up
Username: jkl
Password: mno
signup successful. You can sign-In Now.
Username: abcdef
Password: password1
Login Successful.

非常感谢！

Answer 1

with open('password.txt', mode='a')as passwords:
        ...
        signin()

文件没有关闭，您尝试登录，因此文件指向最后一个索引，您无法读取任何数据。将其更改为

with open('password.txt', mode='a')as passwords:
    password = (input("Password: "))
    passwords.write(f'{password}\n')
    print("signup successful. You can sign-In Now.")
signin()

应该可以解决这个问题。

使用文本文件创建 Python 登录系统

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