Python In 30 Days - Day 8

18 May, 2026

Day eight was about using the built-in JSON module within Python. It wasn't too much different from day seven, so I decided to delete the code for writing to a .txt file and write the methods related to JSON dumping and reading from scratch.

The Challenge:

Replace your plain text file methods with JSON versions:

1. Add a method save_to_json(self, filename) that saves a dictionary containing:

"restaurant": the name
"order": the current order list
"total": the current total
"saved_at": the current date and time as a string

2. Add a method load_from_json(self, filename) that:

Loads the JSON file
Restores self.order from it
Prints the restaurant name, how many items were loaded, and what the saved total was
Handles FileNotFoundError gracefully

3. Create an instance, add items, save to JSON, then load into a fresh instance and verify the order and total match

4. After loading, print the raw JSON file contents as a string so you can see the structure — use json.dumps() with indent=4 for this

My Code:

import json
from datetime import datetime


class Restaurant:
    def __init__(self, name, menu):
        self.name = name
        self.menu = menu
        self.order = []

    def add_item(self, item_name):

        try:
            price = self.menu[item_name]
        except TypeError:
            print(f"Sorry, {item_name} is not a string.\n")
        except KeyError:
            print(f"Sorry, {item_name} is not on the menu!\n")
        else:
            self.order.append(item_name)

        print(f"Added {item_name} to order.")

    def print_order(self):
        print("\nYour Order:")
        print(*self.order, sep="\n")

    def get_total(self):
        if not self.order:
            print("\nWarning: Your order is empty.\n")
            return 0

        total = 0

        for i in self.order:
            try:
                total += self.menu[i]
            except KeyError:
                print(f"Warning: {i} is not on the menu. Skipping item.")
        return total

    def __str__(self):
        menu_len = len(self.menu)
        order_len = len(self.order)
        return f"{self.name} | Menu Items: {menu_len} | Current Order: {order_len}"

    def save_to_json(self, filename):
        now = datetime.now()
        data = {
            "restaurant": f"{self.name}",
            "order": self.order,
            "total": self.get_total(),
            "saved_at": now.strftime("%Y-%m-%d, %I:%M %p"),
        }

        with open(f"{filename}", "w") as f:
            json.dump(data, f, indent=4)

    def load_from_json(self, filename):
        try:
            with open(f"{filename}", "r") as f:
                loaded_data = json.load(f)
                total = loaded_data["total"]
                self.order = loaded_data["order"]
                len_order = len(self.order)

                print("\nReloading Order...")
                print(
                    f"\n{self.name} | Items in Order: {len_order} | Your Total: ${total}\n"
                )

                dump = json.dumps(loaded_data, indent=4)
                print(f"Saved order info:\n {dump}")
        except FileNotFoundError:
            print("Sorry, file not found")


mario = Restaurant(
    "Mario's Restaurant",
    {"Pizza": 12, "Breadsticks": 8, "Salad": 6, "Tiramisu": 4, "Wine": 18},
)
print("Welcome to Mario's Restaurant\n\nAdd items to order?\n")
mario.add_item("Pizza")
mario.add_item("Tiramisu")

total = mario.get_total()
print(f"\nYour total: ${total}")

mario.save_to_json("data.json")


new_mario = Restaurant(
    "Mario's Restaurant",
    {"Pizza": 12, "Breadsticks": 8, "Salad": 6, "Tiramisu": 4, "Wine": 18},
)

print("\nOrder lost...")
new_mario.load_from_json("data.json")

Running the Code:

Welcome to Mario's Restaurant

Add items to order?

Added Pizza to order.
Added Tiramisu to order.

Your total: $16

Order lost...

Reloading Order...

Mario's Restaurant | Items in Order: 2 | Your Total: $16

Saved order info:
 {
    "restaurant": "Mario's Restaurant",
    "order": [
        "Pizza",
        "Tiramisu"
    ],
    "total": 16,
    "saved_at": "2026-05-17, 03:04 PM"
}

I tried to make the readout a little more interesting this time, but either way, I was able to meet the challenge and refresh my memory on I/O for JSON.

Day nine is all about external libraries and API's!

#AI #Challenge #Claude #Coding #Growth #OOP #Python