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

Posted by dfeem
dfeem
4,660 Points

My list doesn't function appropriately. I've watched video over and over, but can't figure out where I messed up?

The following is what I ran in the REPL, but it doesn't function as it's supposed to. It functions a little, but not how it does in video. Please give any insight on what I did wrong?

import os

shopping_list = []

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

def show_help(): clear_screen() print("This list is for you to list whatever:") print("""

  • Enter 'DONE' to stop adding items.
  • Enter 'HELP' for help using this app.
  • Enter 'SHOW' to show items in list. """)

def add_to_list(item): show_list() if len(shopping_list): position = input("Where should I add {}?\n" "Press 'ENTER' to add to 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)

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()

Brennan White
Brennan White
11,646 Points
Brennan White
Brennan White
11,646 Points

Hey can you be more specific about what is not working properly?

dfeem
dfeem
4,660 Points

Sure, The, 'DONE', 'SHOW' and 'HELP' prompts don't work as they do in video. To the best of my knowledge, all the functionality code that I wrote is identical to the code in video.

Thanks!

nico teuben
nico teuben
2,509 Points
nico teuben
nico teuben
2,509 Points

Can you post the entire file ?

dfeem
dfeem
4,660 Points

Yep, I sure can. I did so with my initial question, but for some reason it came out weirdly.

import os

shopping_list = []

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

def show_help(): clear_screen() print("This list is for you to list whatever:") print("""

  • Enter 'DONE' to stop adding items.
  • Enter 'HELP' for help using this app.
  • Enter 'SHOW' to show items in list. """)

def add_to_list(item): show_list() if len(shopping_list): position = input("Where should I add {}?\n" "Press 'ENTER' to add to 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)

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()

dfeem
dfeem
4,660 Points

It came out the same way. I don't know why.

4 Answers

Brennan White
Brennan White
11,646 Points
Brennan White
Brennan White
11,646 Points

You can reference the Markdown Cheatsheet to see why what you are posting is coming out weird. You use three backpacks to start and end code sections.

I reformatted your code and tested it out. Looks like you were running a clear_screen() in show_help(). Take that out and everything works. 

import os

shopping_list = []

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

def show_help(): 
    #clear_screen() 
    print("This list is for you to list whatever:") 
    print("""

Enter 'DONE' to stop adding items.
Enter 'HELP' for help using this app.
Enter 'SHOW' to show items in list. """)
def add_to_list(item): 
    show_list() 
    if len(shopping_list): 
        position = input("Where should I add {}?\n" "Press 'ENTER' to add to 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)

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()
dfeem
dfeem
4,660 Points

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)

I found the problem. I forgot to put 'show_list()' right here. Once I did, everything worked well.

show_list()

dfeem
dfeem
4,660 Points
dfeem
dfeem
4,660 Points

I took that out 'clear screen' out, but it still doesn't function correctly. I'll mess around with it some more.

Brennan White
Brennan White
11,646 Points
Brennan White
Brennan White
11,646 Points

Did you use the code that I posted? It seemed to be working fine to me.

Lawrence Maripfonde
Lawrence Maripfonde
8,102 Points
Lawrence Maripfonde
Lawrence Maripfonde
8,102 Points

Yeah you are right @Brennan, I guess need to rectify that line of code. Thank you very much.

Lawrence Maripfonde
Lawrence Maripfonde
8,102 Points
Lawrence Maripfonde
Lawrence Maripfonde
8,102 Points

The error is on indexing. Try this line of code instead of insert(position-1, item)

if position is not None:
    shopping_list.insert(-1, item)
else:
    shopping_list.append(new_item)
Brennan White
Brennan White
11,646 Points
Brennan White
Brennan White
11,646 Points

Your approach will place the item at the end rather than in a desired position. You are merely appending two different ways.

dfeem
dfeem
4,660 Points

if position is not None: shopping_list.insert(position-1, item) else: shopping_list.append(new_item)

I forgot to put "show_list()" in this position. Once done, it works fine.