使用 exit()，我得到“ValueError: I/O operation on closed file”。

Question

我正在学习 Python，并且在尝试构建身份验证器（登录）时遇到了这个错误。

credentials = {
    "Peter" : "123",
    "Chris" : "Ga1",
    "Michael" : "uwu",
    "Steve" : "xdx10"
}
entered_username = None
entered_password = None
username_errors = 0
password_errors = 0

while True:
    entered_username = input("Please enter your username: ")
    entered_password = input("Please enter your password: ")
    try:
        if entered_password != credentials[entered_username]:
            password_errors += 1
            if password_errors == 5:
                print("Your account has been locked for security reasons.")
                exit()
            print("Wrong username or password, try again.")
            continue
        else:
            print("success 1")
    except:
        username_errors += 1
        if password_errors + username_errors == 5:
            print("Please try again at a later time.")
        print("Wrong username or password, try again.")
        continue
    print("Welcome {}! Your password is {}.".format(entered_username, entered_password))
    break

所以有问题的 exit() 大约是代码的一半，在 if 块的 if 块中 try 块。

运行代码并输入正确密码五次失败应该会显示“您的帐户已因安全原因被锁定”。然后退出代码。但是，它会进行这种追溯。

如果我拿走exit()，回溯就会消失。

我不知道是不是因为try/except，但我已经尝试解决这个问题了一个小时，我快要死在里面了（ಠ_ಠ）。

编辑：没有粘贴回溯（facepalm）

Your account has been locked for security reasons.
Wrong username or password, try again.
Please enter your username: Traceback (most recent call last):
  File "C:/Users/myname/PycharmProjects/stem1401python/py200603/login_form_v3/stem1401_python_login_form_v3.py", line 42, in <module>
    entered_username = input("Please enter your username: ")
ValueError: I/O operation on closed file.

我还要补充一点：我不知道为什么它在 exit() 之后仍然打印出东西。就像在print("Your account has been locked for security reasons.") 之后有exit()

Answer 1

Your account has been locked for security reasons.
Wrong username or password, try again.
Please enter your username: Traceback (most recent call last):
  File "C:/Users/myname/PycharmProjects/stem1401python/py200603/login_form_v3/stem1401_python_login_form_v3.py", line 42, in <module>
    entered_username = input("Please enter your username: ")
ValueError: I/O operation on closed file.

上面的错误是由于pycharm ide当它到达文件中的exit()行时它只是closes the file not terminates the running process所以当它到达 continue 时它会回到循环并尝试获取 input()它@ 987654325@，所以如果你使用idle运行文件，它将成功运行而没有回溯，因为it will automatically kill the running process when file is exited，或者如果你想在pycharm中运行代码只需使用os.abort()而不是exit()，因为它将中止进程

credentials = {
    "Peter" : "123",
    "Chris" : "Ga1",
    "Michael" : "uwu",
    "Steve" : "xdx10"
}
entered_username = None
entered_password = None
username_errors = 0
password_errors = 0
import os
while True:
    entered_username = input("Please enter your username: ")
    entered_password = input("Please enter your password: ")
    try:
        if entered_password != credentials[entered_username]:
            password_errors += 1
            if password_errors == 5:
                print("Your account has been locked for security reasons.")
                os.abort()
            print("Wrong username or password, try again.")
            continue
        else:
            print("success 1")
    except:
        username_errors += 1
        if password_errors + username_errors == 5:
            print("Please try again at a later time.")
        print("Wrong username or password, try again.")
        continue
    print("Welcome {}! Your password is {}.".format(entered_username, entered_password))
    break