Question

我正在尝试制作一个可以添加，删除并查看用户输入的菜肴的程序。但是，看起来很简单，我的while循环遇到了问题。当我键入add时，我可以将项目添加到列表中，但是，当我键入view时，addDish函数将继续循环播放。我以为我用if语句修复了它，但是缺少了某些东西...！

dish_list = []

user_input = ''

def addDish(dish_list):

    user_input = input("Please type the dish you want: ")

    dish_list.append(user_input)

#def deleteDish(dish_list):

def viewDish(dish_list):

    for i in range(len(dish_list)):

        print(dish_list[i])

user_input = input("Please enter a command: ")

while True:

    if user_input == '':

        user_input = input("Please enter a command: ")

    elif user_input == 'add':

        addDish(dish_list, user_input)

    elif user_input == 'view':

        viewDish(dish_list)

Answer 1

您应该调用一个在处理完先前的输入后要求用户输入的函数，而不是使用while循环。

dish_list = []

def addDish(dish_list):

    user_input = input("Please type the dish you want: ")

    dish_list.append(user_input)

#def deleteDish(dish_list):

def viewDish(dish_list):

    for i in range(len(dish_list)):

        print(dish_list[i])

def get_input(): 

    user_input = input("Please enter a command: ")

    if user_input == 'add':

        addDish(dish_list, user_input)

    elif user_input == 'view':

        viewDish(dish_list)

    getInput()

getInput()

Answer 2

更清洁：

dish_list = []


def add_dish(dish_list):
    user_input = input("Please type the dish you want: ")
    dish_list.append(user_input)


def view_dish(dish_list):
    # for dish in dish_list:
    #     print(dish)
    print('\n'.join(dish_list))


while True:
    user_input = input("Please enter a command: ")

    if user_input == 'add':
        add_dish(dish_list)
    elif user_input == 'view':
        view_dish(dish_list)
    else:
        print("Unknown command %s" % user_input)

Answer 3

您的变量user_input永远不会恢复为空，因此您永远都不能输入新命令，因为它只接受您输入到user_input的最后一个条目，这就是在addDish函数中读取的菜式。此外，您对addDish的调用还有一个额外的参数。我还建议将所有内容都放在主要方法中。

def addDish(dish_list):

    user_input = input("Please type the dish you want: ")

    dish_list.append(user_input)


def viewDish(dish_list):

    for i in range(len(dish_list)):

    print(dish_list[i])


def main():

dish_list = []

while True:

    user_input = ''

    if user_input == '':

         user_input = input("Please enter a command: ")

    elif user_input == 'add':

         addDish(dish_list)

    elif user_input == 'view':

         viewDish(dish_list)


main()

Answer 4

以下是上述代码段的固定版本：

def addDish(dish_list):
    user_input = raw_input("Please type the dish you want: ")
    dish_list.append(user_input)

#def deleteDish(dish_list):

def viewDish(dish_list):
    for dish in dish_list:
        print(dish)

dish_list = []

while True:
    user_input = raw_input("Please enter a command: ")
    if user_input == 'add':
        addDish(dish_list)
    elif user_input == 'view':
        viewDish(dish_list)
    elif user_input == 'exit':
        print('Over!')
        break
    else:
        print('Wrong entry. Retry...')

执行输出：

$python so.py
Please enter a command: add
Please type the dish you want: Bread
Please enter a command: add
Please type the dish you want: Burger
Please enter a command: view
Bread
Burger
Please enter a command: foo
Wrong entry. Retry...
Please enter a command: exit
Over!
$

如何在while循环python中切换功能

4 个答案: