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

Posted by Casey Jones
Casey Jones
762 Points

Can't add an item to my list without getting an Attribute Error.

I understand the video and the code, but can't seem to figure out the error below.

import os


shopping_list =()

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


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(new_item)

    show_list()

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)

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.
""")


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()

add_to_list(new_item)

When I run it...I get the show_help prompts

#What should we pick up at the store?                                                                     

Enter 'DONE' to stop adding items.                                                                       
Enter 'HELP' for this help.                                                                              
Enter 'SHOW" to see your current list.

But when I try and input an item it gives me this error that I'm not sure how to fix.

Here's your list:                                                                                        
----------                                                                                               
Traceback (most recent call last):                                                                       
  File "shopping_list.py", line 64, in <module>                                                          
    add_to_list(new_item)                                                                                
  File "shopping_list.py", line 24, in add_to_list                                                       
    shopping_list.insert(position-1, item)                                                                       
AttributeError: 'tuple' object has no attribute 'insert'

Can someone please help? Thanks in advance. :)

2 Answers

caits
caits
4,578 Points

At the very beginning, you declare "shopping_list" as a tuple, not a list. Lists use [] instead of (). You're getting an attribute error because tuples are immutable.

Casey Jones
Casey Jones
762 Points
Casey Jones
Casey Jones
762 Points

Ah! Of course. Thanks Caitlin, I really appreciate it!