Question

我是python和stackoverflow的新手，如果我不太了解，请道歉。我最近选择了Python，并开始使用它。我一直试图登录管理员的东西，但我似乎得到一个错误。我尝试过使用for语句，但我似乎得到了错误：TypeError：＆＃39; str＆＃39;对象不可调用这是我的代码......

username = input("Please enter your username: ")
for name in username (3):
    if username == 'admin':
        break
    else:
        print("You've given incorrect credentials thrice.")
        import sys
        sys.exit("Exiting...")
while True:
    password = input("Please enter your password: ")
    if password == 'KhS9':
        break

print("Welcome admin!")

对此有何帮助？

修改的

道歉，如果我不清楚，我试图尝试制作你需要输入的东西.for循环用于尝试得到句子＆＃34;请输入你的用户名＆＃34;重复3次，然后显示句子＆＃34;你已经给出了3次不正确的凭据＆＃34;如果输入与我设置的输入不匹配（我将其设置为＆＃39; admin＆＃39;）

Answer 1

嗯，那是什么？

DateTimeFormatter

java.sql.Date sqlDate = java.sql.Date.valueOf( localDate );是一个字符串，而不是函数。

如果您想要三首字母，请执行

username = username [3]

脚本：

for name in username (3):

Answer 2

我想你想要

for i in range(3):
    #some code

这意味着放置一些代码的代码将运行三次。但是，你的else语句将评估为true，从而在第一次运行时打破循环。这意味着你需要以某种方式修改它 - 添加一个计数器变量。

在输入正确的密码之前，请考虑运行while True循环。不安全？

只需要语法上的东西 - 即使它意味着你不使用它，也可以在模块顶部（页面）导入一些东西。

Answer 3

以下是您如何正确实施该想法的示例： admin_name ='abc'＃默认用户名（未加密=不安全）。 admin_pass ='cde'＃默认密码（未加密=不安全）。

max_attempts = 3     # Maximum number of times a user can try.
attempt = 0          # Initial condition when the programme is launched.

# Hereby, we'll take invalid attempts as an error, but instead of breaking the
# programme, we will later handle (via "exceptions" the error, and issue
# additional guidance.
try:

    # This is an event loop. It will run for as long as the condition set is true.
    while attempt < max_attempts:

        uname = input('Username: ')  # User is directed to enter the username.
        password = input('pass: ')   # User is directed to enter the password.

        # Values entered by the user are validated.
        if uname == admin_name and password == admin_pass:
            # If the entries are valid, the event loop is broken, and anything
            # written afterwards ( after the exceptions) will now be executed,
            # unless directed otherwise (e.g. a certain function is called)
            # before the "break".
            print('Welcome Admin')
            break

        else:
            # If the entries are invalid, but the maximum number of attempts
            # are not reached, one is added to the attempts, followed by a
            # warning. "continue" means that the rest of the loop is no longer
            # executed, and the event loop automatically moves onto the
            # forthcoming loop immediately. This is not essential here, but I
            # put it in case something else is added to the event loop.
            attempt += 1

            if attempt == max_attempts:
                # if the maximum number of attempts are reached in this loop, a
                # warning is displayed, and the next cycle would not be run
                # automatically. It is best to terminate the programme afterwards,
                # so the following code wouldn't run.
                raise RuntimeError("\nYou've reached the maximum number of attempts allowed.")

            else:
                print('Wrong credentials.\n Try again or press <ctrl+c> to exit.\n')
                continue


except KeyboardInterrupt:
    # "KeyboardInterrupt" is a special exception raised only when the
    # programme is broken out of using <ctrl+c>. In that case, this piece of
    # code is  run.
    print('Terminated by the user.\nGood-bye.')

except RuntimeError as e:
    # This is handling of the errors raised above. The value of "e" is equal
    # the value given to the relevant function (RuntimeError in this case)
    # when it was raised.
    print(e)

不用说，这是一种存储管理员密码的不安全方式。也许利用Python的crypt模块来加密密码？

Python错误：TypeError：＆＃39; str＆＃39;对象不可调用

3 个答案: