当用户提供某个关键字作为输入时结束函数

Question

当用户在输入中键入特定关键字（例如 'off'）时，我如何结束函数而不必在每个输入中添加必要的代码？基本上我希望当用户在下面的任何输入中的任何地方键入单词 'off' 时该功能完全停止。我已经创建了一个函数（见代码底部）并在我的代码中尝试了 placing/calling 但我不确定将它放在哪里或者我是否可以用一个函数来做到这一点？如果没有，我该如何实现？

  def order_coffee():

    drink = input("What would you like? (espresso/latte/cappuccino): ")

    user_owes = int(0)

    if drink == "espresso":
        user_owes = round(1.5, 2)
    elif drink == "latte":
        user_owes = round(2.5, 2)
    elif drink == "cappuccino":
        user_owes = round(3.0, 2)

    print(f"Please insert coins, you owe ${user_owes}.")
    quarters = (int(input("How many quarters?: ")) * .25)
    dimes = (int(input("How many dimes?: ")) * .1)
    nickels = (int(input("How many nickels?: ")) * .05)
    pennies = (int(input("How many pennies?: ")) * .01)

    user_paid = round(quarters + dimes + nickels + pennies, 2)
    print(f"You have inserted ${user_paid}.")
    change = round(user_paid - user_owes, 2)

    if user_paid >= user_owes:
        print(f"Here is ${change} in change.")
        print(f"Here is your {drink} ☕. Enjoy!")
        order_coffee()
    else:
        print("Sorry that's not enough money. Money refunded.")
        order_coffee()
        
order_coffee()

 def off():
        if input == "off":
            return

Answer 1

创建您自己的 input 函数并添加所需的行为：

def my_input(*args, **kwargs):
    str = input(*args, **kwargs)
    if str == "off":
        exit()
    return str

当用户输入为“关闭”时，这将从整个应用程序退出，仅从函数退出而不是抛出异常，并在函数调用之外捕获它。例如：

def my_input(*args, **kwargs):
    str = input(*args, **kwargs)
    if str == "off":
        raise ValueError('Time to go')

和：

  def order_coffee():
      try:
          # your code
       except ValueError as err:
          # handle it accordingly
          return

更清晰的方法是创建、抛出和处理自定义 Exception。看看这个 SO Thread 以了解如何实现这些自定义异常。

Answer 2

def order_coffee():

    drink = input("What would you like? (espresso/latte/cappuccino): ")

    user_owes = int(0)

    if drink == "espresso":
        user_owes = round(1.5, 2)
    elif drink == "latte":
        user_owes = round(2.5, 2)
    elif drink == "cappuccino":
        user_owes = round(3.0, 2)
    elif drink == 'off':
        return None

    print(f"Please insert coins, you owe ${user_owes}.")
    quarters = (int(input("How many quarters?: ")) * .25)
    dimes = (int(input("How many dimes?: ")) * .1)
    nickels = (int(input("How many nickels?: ")) * .05)
    pennies = (int(input("How many pennies?: ")) * .01)

    user_paid = round(quarters + dimes + nickels + pennies, 2)
    print(f"You have inserted ${user_paid}.")
    change = round(user_paid - user_owes, 2)

    if user_paid >= user_owes:
        print(f"Here is ${change} in change.")
        print(f"Here is your {drink} ☕. Enjoy!")
        order_coffee()
    else:
        print("Sorry that's not enough money. Money refunded.")
        order_coffee()
        
    

order_coffee()

Answer 3

您可以创建自己的输入函数来检查这一点，并在输入事件 'off' 时退出程序。这样，如果有人在程序中的任何时候输入 "off"，它就会结束。

import sys

def get_input(text):
    user_feedback = input(text)
    if user_feedback == 'off':
        sys.exit()
    return user_feedback


def order_coffee():

    print("Welcome to the coffee robot! (type 'off' to exit at any time)")
    drink = get_input("What would you like? (espresso/latte/cappuccino): ")

    user_owes = int(0)

    if drink == "espresso":
        user_owes = round(1.5, 2)
    elif drink == "latte":
        user_owes = round(2.5, 2)
    elif drink == "cappuccino":
        user_owes = round(3.0, 2)

    print(f"Please insert coins, you owe ${user_owes}.")
    quarters = (int(get_input("How many quarters?: ")) * .25)
    dimes = (int(get_input("How many dimes?: ")) * .1)
    nickels = (int(get_input("How many nickels?: ")) * .05)
    pennies = (int(get_input("How many pennies?: ")) * .01)

    user_paid = round(quarters + dimes + nickels + pennies, 2)
    print(f"You have inserted ${user_paid}.")
    change = round(user_paid - user_owes, 2)

    if user_paid >= user_owes:
        print(f"Here is ${change} in change.")
        print(f"Here is your {drink} ☕. Enjoy!")
        order_coffee()
    else:
        print("Sorry that's not enough money. Money refunded.")
        order_coffee()


order_coffee()

当用户提供某个关键字作为输入时结束函数

End a function when the user provides a certain keyword as input

python

input

output