Пытаться заменить элемент в списке другим товаром

Question

Я пытаюсь заменить элемент в списке не обязательно в конце, просто позицию исходного элемента, а затем потребовать новый элемент, когда он просит вас для вашего пароля. Я новичок в Python.

passwords = ['mrjoebblock' , 'mrjoefblock' , 'mrjoegblock', 'mrjoeadmin' ] 
if choice == '3': 
     password = raw_input('Welcome admin! I\'m going to need your password ') 
     if password == 'mrjoeadmin': 
      print('Welcome Mr. Joe!') 
      Choice11 = raw_input('What would you like to do? Press 1 for changing your admin password, 2 for viewing a class\'s comments, or 3 for changing a class\'s password') 
      if Choice11 == '1': 
       print('You have chosen to change your password! ') 
       Choice12 = raw_input('You will need to put in your current password to access this feature ') 
       if Choice12 == 'mrjoeadmin': 
        Choice13 = raw_input('What would you like to change your password to? ') 
        passwords.remove('mrjoeadmin') 
        passwords.append(Choice13) 
        print('Thank you! Password has been changed. Log in with new password next time') 
        break 
      if Choice11 == '2': 
       print('you have chosen to view a class\'s comments!') 
       Choice14 = raw_input('Which block would you like to view?') 
       if Choice14 == 'F block': 
        print('To view F block\'s comments, go to where you search for things in your computer, and search CommentsFblock.txt. Open it') 
        time.sleep(10) 
        break 
       if Choice14 == 'G block': 
        print('To view G block\'s comments, go to where you search for things in your computer, and search CommentsGblock.txt. Open it') 
        time.sleep(10) 
        break 
       if Choice14 == 'B block': 
        print('To view B block\'s comments, go to where you search for things in your computer, and search CommentsBblock.txt. Open it') 
        time.sleep(10) 
        break 
       else: 
        print('I\'m sorry, that\'s not a valid block name.') 
        time.sleep(2) 
        break 
      if Choice11 == '3': 
       print('you have chosen to change a block\'s password.') 
       Choice15 = raw_input('Which block\'s password would you like to change?') 
       if Choice15 == 'F block': 
        Choice16 = raw_input('You will need to put in your current password to change F block\'s password ') 
        if Choice16 == 'mrjoeadmin': 
         Choice17 = raw_input('What would you like to change F block\'s password to? ') 
         passwords.remove('mrjoefblock') 
         passwords.append(Choice17) 
         print('Thank you! Password has been changed. Remember to tell students the password has been changed') 
         time.sleep(3) 
         break 
       if Choice15 == 'G block': 
        Choice18 = raw_input('You will need to put in your current password to change G block\'s password ') 
        if Choice18 == 'mrjoeadmin': 
         Choice19 = raw_input('What would you like to change G block\'s password to? ') 
         passwords.remove('mrjoegblock') 
         passwords.append(Choice19) 
         print('Thank you! Password has been changed. Remember to tell students the password has been changed') 
         time.sleep(3) 
         break 
       if Choice15 == 'B block': 
        Choice20 = raw_input('You will need to put in your current password to change B block\'s password ') 
        if Choice20 == 'mrjoeadmin': 
         Choice21 = raw_input('What would you like to change B block\'s password to? ') 
         passwords.remove('mrjoebblock') 
         passwords.append(Choice21) 
         print('Thank you! Password has been changed. Remember to tell students the password has been changed') 
         time.sleep(3) 
         break 

Answer 1

Для замены элемента в списке, просто назначить его по списку своей позиции:

mylist = ['hello', 'goodbye', 'goodnight'] 

mylist[2] = 'good day' 

Answer 2

Если вы знаете значение элемента в списке (скажем вы собираетесь изменить пароль F Блока, 'mrjoefblock'), вы можете использовать list.index() функцию, чтобы вернуть его индекс, просто так:

In [1]: passwords = ['mrjoebblock' , 'mrjoefblock' , 'mrjoegblock', 'mrjoeadmin' ] 

In [2]: passwords.index('mrjoefblock') 
Out[2]: 1 

In [3]: passwords[passwords.index('mrjoefblock')] = 'newjoefblock' 

In [4]: passwords 
Out[4]: ['mrjoebblock', 'newjoefblock', 'mrjoegblock', 'mrjoeadmin'] 

Таким образом, вы будете иметь возможность обновить пароль и сохранить на том же самом Positio n (если это то, что вы просите).

Но мне кажется странным менять такие пароли. Я бы сделал это не список, но словарь вместо:

In [1]: credentials = { 
    ...:  'B Block': 'mrjoebblock', 
    ...:  'F Block': 'mrjoefblock', 
    ...:  'G Block': 'mrjoegblock', 
    ...:  'Admin': 'mrjoeadmin' 
    ...: } 

Теперь мы можем найти всех пользователей с данным паролем:

In [2]: [user for user, password in credentials.iteritems() if password == 'mrjoeadmin'] 
Out[2]: ['Admin'] 

И изменить пароль для любого пользователя достаточно легко:

In [3]: credentials['F Block'] = 'newjoefblock' 

In [4]: credentials 
Out[4]: 
{'Admin': 'mrjoeadmin', 
'B Block': 'mrjoebblock', 
'F Block': 'newjoefblock', 
'G Block': 'mrjoegblock'} 

---

К сожалению, это было изначально неясно, что вы просите.

Я придумал этот простой пример:

def login(): 
    """ 
    This function asks for the password and returns either the username (if logged in successfully) 
    or False (if the password was incorrect). 
    """ 
    password = raw_input("Password: ") 

    if password == 'admin': 
     return 'Administrator' 
    elif password == 'ggguest': 
     return 'Guest' 
    else: 
     return False 


if __name__ == '__main__': 
    # We'll introduce a new variable which will be either a logged in user's name 
    # or False (based on login()'s function result) 
    user_logged_in = login() 

    while True: # An endless loop 
     if user_logged_in: 
      # the login() function didn't return False, so we're logged in! 
      print "Yay! You're now logged in as {0}!".format(user_logged_in) 

      # Here we'll do whatever you need to. 
      # I kept the example simple so it just asks if the user wants to log out. 
      # You can change the user's password here and ask for the password again. 

      want_to_logout = raw_input("Want to log out? [y/n]: ") 

      if want_to_logout == 'y': 
       user_logged_in = login() # Ask for the password again 
      else: 
       print 'Alright then! Do your thing!' 
       break # Break out of loop and continue 
     else: 
      # wrong password, ask again 
      print "Wrong password :(" 
      user_logged_in = login() # Ask for the password again 

    print "Keep up the good job, {0}!".format(user_logged_in) 

И вот как это работает:

$ python admin.py 
Password: wrong_password 
Wrong password :(
Password: admin 
Yay! You're now logged in as Administrator! 
Want to log out? [y/n]: y 
Password: ggguest 
Yay! You're now logged in as Guest! 
Want to log out? [y/n]: n 
Alright then! Do your thing! 
Keep up the good job, Guest! 

Таким образом, вы можете продолжать спрашивать у пользователя пароль, если это необходимо и по-прежнему в противном случае.