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Python Python Collections (2016, retired 2019) Lists Shopping List Take Three

2 issues in this lesson

I have two problems with my code in this lesson that are driving me crazy.

  1. When I type in a new item and hit enter, the add_to_list function doesn't show the new item in the string asking where to add the new item (e.g. where should I add?, as opposed to where should I add apple?)

  2. When I add my first item, and hit enter, the show_list function doesn't show any items in my list, just "Here's your list:" then the dashes. Once I add another item the list starts printing the complete list.

I have watched the complete video several times and I can't see where my code differs.

```import os

shopping_list = []

def clear_screen(): os.system("cls" if os.name == "nt" else "clear")

def show_help(): clear_screen() 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 add_to_list(item): show_list()

if len(shopping_list): position = input("Where should I add {}? \n" "Press Enter to add to the end of the list \n" "> ".format(item))

else: position = 0

try: position = abs(int(position)) except ValueError: position = None if position is not None: shopping_list.insert(position - 1, item) else: shopping_list.append(item)

def show_list(): clear_screen()

print("Here's your list:")

index = 1

for item in shopping_list:
    print("{}. {}".format(index, item))
    index += 1

print("-"*10)

show_help()

while True: new_item = input("> ")

if new_item.upper() == 'DONE' or new_item.upper() == 'QUIT':
    break
elif new_item.upper() == 'HELP':
    show_help()
    continue
elif new_item.upper() == 'SHOW':
    show_list()
    continue
else:
  add_to_list(new_item)

show_list()```

1 Answer

Steven Parker
Steven Parker
229,657 Points

The input statement seems to contain 3 separate strings, but the "format" will only work on the last one. Use just one string instead:

# original
input("Where should I add {}? \n" "Press Enter to add to the end of the list \n" "> ".format(item))
# fixed
input("Where should I add {}?\nPress Enter to add to the end of the list\n> ".format(item))

The control flow issue will be difficult to diagnose in unformatted code. Edit your code to apply Markdown formatting as described in the Markdown Cheatsheet pop-up below the "Add an Answer" area. :arrow_heading_down:   Or watch this video on code formatting.