Pizza Py

Perhaps the most popular place for pizza in Harvard Square is Pinocchio’s Pizza & Subs, aka Noch’s, known for its Sicilian pizza, which is “a deep-dish or thick-crust pizza.”

Students tend to buy pizza by the slice, but Pinocchio’s also has whole pizzas on its menu too, per this CSV file of Sicilian pizzas, sicilian.csv, below:

Sicilian Pizza,Small,Large
1 item,$27.50,$41.95
2 items,$29.50,$43.95
3 items,$31.50,$45.95

See regular.csv for a CSV file of regular pizzas as well.

Of course, a CSV file isn’t the most customer-friendly format to look at. Prettier might be a table, formatted as ASCII art, like this one:

| Sicilian Pizza   | Small   | Large   |
| Cheese           | $25.50  | $39.95  |
| 1 item           | $27.50  | $41.95  |
| 2 items          | $29.50  | $43.95  |
| 3 items          | $31.50  | $45.95  |
| Special          | $33.50  | $47.95  |

In a file called, implement a program that expects exactly one command-line argument, the name (or path) of a CSV file in Pinocchio’s format, and outputs a table formatted as ASCII art using tabulate, a package on PyPI at Format the table using the library’s grid format. If the user does not specify exactly one command-line argument, or if the specified file’s name does not end in .csv, or if the specified file does not exist, the program should instead exit via sys.exit.



Before You Begin

Log into, click on your terminal window, and execute cd by itself. You should find that your terminal window’s prompt resembles the below:


Next execute

mkdir pizza

to make a folder called pizza in your codespace.

Then execute

cd pizza

to change directories into that folder. You should now see your terminal prompt as pizza/ $. You can now execute


to make a file called where you’ll write your program. Be sure to run


to download sicilian.csv into your folder. Also run


to download regular.csv into your folder.

How to Test

Here’s how to test your code manually:

  • Run your program with python Your program should exit using sys.exit and provide an error message:
    Too few command-line arguments
  • Be sure to download regular.csv and sicilian.csv, placing them in the same folder as Run your program with python regular.csv sicilian.csv. Your program should output:
    Too many command-line arguments
  • Run your program with python invalid_file.csv. Assuming invalid_file.csv doesn’t exist, your program should exit using sys.exit and provide an error message:
    File does not exist
  • Create a file named sicilian.txt. Run your program with python sicilian.txt. Your program should exit using sys.exit and provide an error message:
    Not a CSV file
  • Run your program with python regular.csv. Assuming you’ve downloaded regular.csv, your program should print a table like the below:
    | Regular Pizza   | Small   | Large   |
    | Cheese          | $13.50  | $18.95  |
    | 1 topping       | $14.75  | $20.95  |
    | 2 toppings      | $15.95  | $22.95  |
    | 3 toppings      | $16.95  | $24.95  |
    | Special         | $18.50  | $26.95  |

You can execute the below to check your code using check50, a program that CS50 will use to test your code when you submit. But be sure to test it yourself as well!

check50 cs50/problems/2022/python/pizza

Green smilies mean your program has passed a test! Red frownies will indicate your program output something unexpected. Visit the URL that check50 outputs to see the input check50 handed to your program, what output it expected, and what output your program actually gave.

How to Submit

In your terminal, execute the below to submit your work.

submit50 cs50/problems/2022/python/pizza