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Python Python Basics (2015) Shopping List App Second Shopping List App

Question about Challenge Task

The task request as below: Create a new function named main that doesn't take any arguments. Move everything from line 22 (show_help()) and below into your new function. You shouldn't have any code that isn't inside of a function.

so I just insert function "def main():" above code show help(), at the bottom of codes, insert main()

I think this should be work, right? but I can't pass the task

def show_help():
    # print out instructions on how to use the app
    print("What should we pick up at the store?")
    print("""
Enter 'DONE' to stop adding items.
Enter 'HELP' for this help.
Enter 'SHOW' to see your current list.
""")

def show_list(shopping_list):
    # print out the list
    print("Here's your list:")

    for item in shopping_list:
        print(item)

def add_to_list(shopping_list, new_item):
    # add new items to our list
    shopping_list.append(new_item)
    print("Added {}. List now has {} items.".format(new_item, len(shopping_list)))
    return shopping_list
def main():    
show_help()

# make a list to hold onto our items
shopping_list = []

while True:
    # ask for new items
    new_item = input("> ")

    # be able to quit the app
    if new_item == 'DONE':
        break
    elif new_item == 'HELP':
        show_help()
        continue
    elif new_item == 'SHOW':
        show_list(shopping_list)
        continue
    add_to_list(shopping_list, new_item)

show_list(shopping_list)

main()

1 Answer

andren
andren
28,558 Points

The problem is that you have not indented the code you moved. Code that belongs to a function has to be indented to be one level deeper than where the function definition is. If you don't then Python won't recognize the code as being part of the function. You are also not meant to have any code below the function, meaning that you are not meant to call the function yourself.

If you fix the indentation and remove the call to the function like this:

def show_help():
    # print out instructions on how to use the app
    print("What should we pick up at the store?")
    print("""
Enter 'DONE' to stop adding items.
Enter 'HELP' for this help.
Enter 'SHOW' to see your current list.
""")

def show_list(shopping_list):
    # print out the list
    print("Here's your list:")

    for item in shopping_list:
        print(item)

def add_to_list(shopping_list, new_item):
    # add new items to our list
    shopping_list.append(new_item)
    print("Added {}. List now has {} items.".format(new_item, len(shopping_list)))
    return shopping_list
def main():    
    show_help()

    # make a list to hold onto our items
    shopping_list = []

    while True:
        # ask for new items
        new_item = input("> ")

        # be able to quit the app
        if new_item == 'DONE':
            break
        elif new_item == 'HELP':
            show_help()
            continue
        elif new_item == 'SHOW':
            show_list(shopping_list)
            continue
        add_to_list(shopping_list, new_item)

    show_list(shopping_list)

Then your code will pass.

Hi Andren,

What you said is right, I've passed, Thank you very much.

but I still don't understand, they request to add a new function, but why no need to insert main() at the bottom of the code, if without main(), then what does the function of main use for? just for show?

andren
andren
28,558 Points

The purpose of this challenge is just to see if you understand how to refactor (in this case simply move) code successfully. The purpose was not really to make a functional program.

HAHA, got it, I thought too much probably.