Python: 用打印语句停止程序
Python: Stopping the program with a print statement
我想在这里完成我的程序，虽然一切都准备就绪，但对于 def endapp() 函数，我不知道如何让它打印 "Goodbye" 来标记程序的结束程序没有 menu() 功能或任何其他功能，如 login() 再次循环。其他一切都按原样工作，但我不知道如何只用打印消息结束程序。我只需要程序在打印 "Goodbye" 后停止输出任何东西，它到达死胡同，而不是使用 sys.exit() 退出整个应用程序。注意：函数 viewapp()、addapp()、summary() 都将循环回到 logged()，我还没有为此添加代码，而 endapp() 应该根本没有循环，应该以"Goodbye" 并且没有其他函数应该循环返回以再次请求输入。提供代码示例，将不胜感激。
vault = {}
def menu():
mode = input("""Hello {}, below are the modes that you can choose from:\n
##########################################################################
a) Login with username and password
b) Register as a new user
To select a mode, enter the corresponding letter of the mode below
##########################################################################\n
> """.format(name)).strip()
return mode
def login():
if len(vault) > 0 : #user has to append usernames and passwords before it asks for login details
print("Welcome to the login console")
while True:
username = input ("Enter Username: ")
if username == "":
print("User Name Not entered, try again!")
continue
password = input ("Enter Password: ")
if password == "":
print("Password Not entered, try again!")
continue
try:
if vault[username] == password:
print("Username matches!")
print("Password matches!")
logged() #jumps to logged function and tells the user they are logged on
except KeyError: #the except keyerror recognises the existence of the username and password in the list
print("The entered username or password is not found!")
else:
print("You have no usernames and passwords stored!")
def register(): #example where the username is appended. Same applies for the password
print("Please create a username and password into the password vault.\n")
while True:
validname = True
while validname:
username = input("Please enter a username you would like to add to the password vault. NOTE: Your username must be at least 3 characters long: ").strip().lower()
if not username.isalnum():
print("Your username cannot be null, contain spaces or contain symbols \n")
elif len(username) < 3:
print("Your username must be at least 3 characters long \n")
elif len(username) > 30:
print("Your username cannot be over 30 characters \n")
else:
validname = False
validpass = True
while validpass:
password = input("Please enter a password you would like to add to the password vault. NOTE: Your password must be at least 8 characters long: ").strip().lower()
if not password.isalnum():
print("Your password cannot be null, contain spaces or contain symbols \n")
elif len(password) < 8:
print("Your password must be at least 8 characters long \n")
elif len(password) > 20:
print("Your password cannot be over 20 characters long \n")
else:
validpass = False #The validpass has to be True to stay in the function, otherwise if it is false, it will execute another action, in this case the password is appended.
vault[username] = password
validinput = True
while validinput:
exit = input("\nEnter 'end' to exit or any key to continue to add more username and passwords:\n> ")
if exit in ["end", "End", "END"]:
return
else:
validinput = False
register()
return register
#LOGGED ONTO THE PASSWORD AND WEBSITE APP ADDING CONSOLE----------------------------------------------------------------------------------
def logged():
print("You are logged in!\n")
keeplooping = True
while keeplooping:
modea = input("""Below are the options you can choose:
##########################################################################\n
1) Viewapp
2) Addapp
3) Summary
4) Exit
##########################################################################\n
> """).strip()
if modea == "1":
viewapp()
elif modea == "2":
addapp()
elif modea == "3":
summary()
elif modea == "4":
keeplooping = False
print("Goodbye")
else:
print("That was not a valid option, please try again: ")
validintro = False
return modea
def viewapp():
print("*Insert viewapp*")
def addapp():
print("*Insert addapp*")
def summary():
print("*Insert summary*")
#Main routine
print("Welcome to the password vault program")
print("In this program you will be able to store your usernames and passwords in password vaults and view them later on.\n")
validintro = False
while not validintro:
name = input("Hello user, what is your name?: ")
if len(name) < 1:
print("Please enter a name: ")
elif len(name) > 30:
print("Please enter a name no more than 30 characters: ")
else:
validintro = True
print("Welcome to the password vault program {}.".format(name))
#The main program to run in a while loop for the program to keep on going back to the menu part of the program for more input till the user wants the program to stop
validintro = False
while not validintro:
chosen_option = menu() #a custom variable is created that puts the menu function into the while loop
validintro = False
if chosen_option in ["a", "A"]:
login()
elif chosen_option in ["b", "B"]:
register()
else:
print("""That was not a valid option, please try again:\n """)
validintro = False
我可以建议你做的是：
1st - 在 logged() 函数中：如果用户选择
elif modea == '4'
keeplooping = False
print('Goodbye')
return keeplooping
第二 - 在 login() 函数中：而不是 while True。你能做的就是
def login():
if len(vault) > 0 : #user has to append usernames and passwords before it asks for login details
print("Welcome to the login console")
state = True
while state:
username = input ("Enter Username: ")
if username == "":
print("User Name Not entered, try again!")
continue
password = input ("Enter Password: ")
if password == "":
print("Password Not entered, try again!")
continue
try:
if vault[username] == password:
print("Username matches!")
print("Password matches!")
state = logged() #jumps to logged function and tells the user they are logged on
return state #return the state of user option (True/False)
except KeyError: #the except keyerror recognises the existence of the username and password in the list
print("The entered username or password is not found!")
else:
print("You have no usernames and passwords stored!")
3rd - 在主程序中 validintro 应该相应地改变
validintro = False
while not validintro:
chosen_option = menu() #a custom variable is created that puts the menu function into the while loop
validintro = False
if chosen_option in ["a", "A"]:
validintro = not login()
elif chosen_option in ["b", "B"]:
register()
else:
print("""That was not a valid option, please try again:\n """)
validintro = False
这是一个很好的技巧，但它必须有效
我想在这里完成我的程序，虽然一切都准备就绪，但对于 def endapp() 函数，我不知道如何让它打印 "Goodbye" 来标记程序的结束程序没有 menu() 功能或任何其他功能，如 login() 再次循环。其他一切都按原样工作，但我不知道如何只用打印消息结束程序。我只需要程序在打印 "Goodbye" 后停止输出任何东西，它到达死胡同，而不是使用 sys.exit() 退出整个应用程序。注意：函数 viewapp()、addapp()、summary() 都将循环回到 logged()，我还没有为此添加代码，而 endapp() 应该根本没有循环，应该以"Goodbye" 并且没有其他函数应该循环返回以再次请求输入。提供代码示例，将不胜感激。
vault = {}
def menu():
mode = input("""Hello {}, below are the modes that you can choose from:\n
##########################################################################
a) Login with username and password
b) Register as a new user
To select a mode, enter the corresponding letter of the mode below
##########################################################################\n
> """.format(name)).strip()
return mode
def login():
if len(vault) > 0 : #user has to append usernames and passwords before it asks for login details
print("Welcome to the login console")
while True:
username = input ("Enter Username: ")
if username == "":
print("User Name Not entered, try again!")
continue
password = input ("Enter Password: ")
if password == "":
print("Password Not entered, try again!")
continue
try:
if vault[username] == password:
print("Username matches!")
print("Password matches!")
logged() #jumps to logged function and tells the user they are logged on
except KeyError: #the except keyerror recognises the existence of the username and password in the list
print("The entered username or password is not found!")
else:
print("You have no usernames and passwords stored!")
def register(): #example where the username is appended. Same applies for the password
print("Please create a username and password into the password vault.\n")
while True:
validname = True
while validname:
username = input("Please enter a username you would like to add to the password vault. NOTE: Your username must be at least 3 characters long: ").strip().lower()
if not username.isalnum():
print("Your username cannot be null, contain spaces or contain symbols \n")
elif len(username) < 3:
print("Your username must be at least 3 characters long \n")
elif len(username) > 30:
print("Your username cannot be over 30 characters \n")
else:
validname = False
validpass = True
while validpass:
password = input("Please enter a password you would like to add to the password vault. NOTE: Your password must be at least 8 characters long: ").strip().lower()
if not password.isalnum():
print("Your password cannot be null, contain spaces or contain symbols \n")
elif len(password) < 8:
print("Your password must be at least 8 characters long \n")
elif len(password) > 20:
print("Your password cannot be over 20 characters long \n")
else:
validpass = False #The validpass has to be True to stay in the function, otherwise if it is false, it will execute another action, in this case the password is appended.
vault[username] = password
validinput = True
while validinput:
exit = input("\nEnter 'end' to exit or any key to continue to add more username and passwords:\n> ")
if exit in ["end", "End", "END"]:
return
else:
validinput = False
register()
return register
#LOGGED ONTO THE PASSWORD AND WEBSITE APP ADDING CONSOLE----------------------------------------------------------------------------------
def logged():
print("You are logged in!\n")
keeplooping = True
while keeplooping:
modea = input("""Below are the options you can choose:
##########################################################################\n
1) Viewapp
2) Addapp
3) Summary
4) Exit
##########################################################################\n
> """).strip()
if modea == "1":
viewapp()
elif modea == "2":
addapp()
elif modea == "3":
summary()
elif modea == "4":
keeplooping = False
print("Goodbye")
else:
print("That was not a valid option, please try again: ")
validintro = False
return modea
def viewapp():
print("*Insert viewapp*")
def addapp():
print("*Insert addapp*")
def summary():
print("*Insert summary*")
#Main routine
print("Welcome to the password vault program")
print("In this program you will be able to store your usernames and passwords in password vaults and view them later on.\n")
validintro = False
while not validintro:
name = input("Hello user, what is your name?: ")
if len(name) < 1:
print("Please enter a name: ")
elif len(name) > 30:
print("Please enter a name no more than 30 characters: ")
else:
validintro = True
print("Welcome to the password vault program {}.".format(name))
#The main program to run in a while loop for the program to keep on going back to the menu part of the program for more input till the user wants the program to stop
validintro = False
while not validintro:
chosen_option = menu() #a custom variable is created that puts the menu function into the while loop
validintro = False
if chosen_option in ["a", "A"]:
login()
elif chosen_option in ["b", "B"]:
register()
else:
print("""That was not a valid option, please try again:\n """)
validintro = False
我可以建议你做的是： 1st - 在 logged() 函数中：如果用户选择
elif modea == '4'
keeplooping = False
print('Goodbye')
return keeplooping
第二 - 在 login() 函数中：而不是 while True。你能做的就是
def login():
if len(vault) > 0 : #user has to append usernames and passwords before it asks for login details
print("Welcome to the login console")
state = True
while state:
username = input ("Enter Username: ")
if username == "":
print("User Name Not entered, try again!")
continue
password = input ("Enter Password: ")
if password == "":
print("Password Not entered, try again!")
continue
try:
if vault[username] == password:
print("Username matches!")
print("Password matches!")
state = logged() #jumps to logged function and tells the user they are logged on
return state #return the state of user option (True/False)
except KeyError: #the except keyerror recognises the existence of the username and password in the list
print("The entered username or password is not found!")
else:
print("You have no usernames and passwords stored!")
3rd - 在主程序中 validintro 应该相应地改变
validintro = False
while not validintro:
chosen_option = menu() #a custom variable is created that puts the menu function into the while loop
validintro = False
if chosen_option in ["a", "A"]:
validintro = not login()
elif chosen_option in ["b", "B"]:
register()
else:
print("""That was not a valid option, please try again:\n """)
validintro = False
这是一个很好的技巧，但它必须有效