Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Python Python Basics (2015) Shopping List App Refactor

Sachin Kanchan
Sachin Kanchan
564 Points
Posted by Sachin Kanchan
Sachin Kanchan
564 Points

Seems like a bug or technical issue in REFACTOR Challenge.

I would like to point out a bug. I successfully completed the Refactor challenge in Python Basics. But there seems to be an issue.

This is the code that works perfectly in WORKSPACE but gives Bummer in objective.

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()

Below is another code, everything is same, except the Indentation of the last line. This COMPLETES the Objective, but does not execute in the Workspace. It just exits the program right away.

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()

Which is the right way to do it?

1 Answer

Jeffrey Duarte
Jeffrey Duarte
9,706 Points
Jeffrey Duarte
Jeffrey Duarte
9,706 Points

Hi Sachin,

Your first example where the call to execute main() is outside of the main() function block is the correct way, and that is why it executes on the workspace. The second is incorrect because you're forcing the execution of main() when the function should be ending.

The reason for the 'error' on the objective side is that we are never instructed to execute main(). We're only supposed to create it. The end result should be that no code actually executes, and i believe that the Objective test is looking for 2 things:

  1. The presence of main()
  2. That no code runs (again only because we were not instructed to run the code.)

I hope this helps.