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Solved Lab | Error Handling #596

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366 changes: 360 additions & 6 deletions lab-python-error-handling.ipynb
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Original file line number Diff line number Diff line change
Expand Up @@ -2,10 +2,11 @@
"cells": [
{
"cell_type": "markdown",
"id": "25d7736c-ba17-4aff-b6bb-66eba20fbf4e",
"id": "40485476",
"metadata": {},
"source": [
"# Lab | Error Handling"
"# Lab | Error Handling\n",
"---"
]
},
{
Expand All @@ -18,8 +19,8 @@
"The implementation of your code for managing customer orders assumes that the user will always enter a valid input. \n",
"\n",
"For example, we could modify the `initialize_inventory` function to include error handling.\n",
" - If the user enters an invalid quantity (e.g., a negative value or a non-numeric value), display an error message and ask them to re-enter the quantity for that product.\n",
" - Use a try-except block to handle the error and continue prompting the user until a valid quantity is entered.\n",
" - **If the user enters an invalid quantity** (e.g., a negative value or a non-numeric value), **display an error message** and **ask them to re-enter** the quantity for that product.\n",
" - Use a **``try-except``** block to handle the error and continue prompting the user **until a valid quantity is entered**.\n",
"\n",
"```python\n",
"# Step 1: Define the function for initializing the inventory with error handling\n",
Expand Down Expand Up @@ -72,11 +73,364 @@
"\n",
"4. Test your code by running the program and deliberately entering invalid quantities and product names. Make sure the error handling mechanism works as expected.\n"
]
},
{
"cell_type": "markdown",
"id": "549c919f",
"metadata": {},
"source": [
"---\n",
"---\n",
"# Solved Lab | Error Handling"
]
},
{
"cell_type": "markdown",
"id": "399e7e87",
"metadata": {},
"source": [
"---\n",
"### STEP 1\n",
"modify the `initialize_inventory` function to include error handling.\n",
" - **If the user enters an invalid quantity** (e.g., a negative value or a non-numeric value), **display an error message** and **ask them to re-enter** the quantity for that product.\n",
" - Use a **``try-except``** block to handle the error and continue prompting the user **until a valid quantity is entered**."
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "4f673274",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Invalid input: invalid literal for int() with base 10: 'a'. Please enter a non-negative integer.\n",
"Invalid input: invalid literal for int() with base 10: 'f'. Please enter a non-negative integer.\n",
"Invalid input: invalid literal for int() with base 10: 'g'. Please enter a non-negative integer.\n",
"Invalid input: invalid literal for int() with base 10: 'apple'. Please enter a non-negative integer.\n",
"Invalid input: invalid literal for int() with base 10: 'Apple'. Please enter a non-negative integer.\n",
"Invalid input: invalid literal for int() with base 10: 'Apples'. Please enter a non-negative integer.\n",
"Invalid input: invalid literal for int() with base 10: 'Cake'. Please enter a non-negative integer.\n",
"Invalid input: invalid literal for int() with base 10: ''. Please enter a non-negative integer.\n",
"Invalid input: invalid literal for int() with base 10: ''. Please enter a non-negative integer.\n"
]
}
],
"source": [
"# Step 1: Define the function for initializing the inventory with error handling\n",
"def initialize_inventory(products):\n",
" \"\"\"\n",
" Initialize inventory quantities for a list of products.\n",
" Ensures that the user enters valid non-negative integers.\n",
" \n",
" Args:\n",
" products (list): List of product names.\n",
" \n",
" Returns:\n",
" dict: Dictionary with product names as keys and quantities as values.\n",
" \"\"\"\n",
" inventory = {}\n",
" \n",
" for product in products:\n",
" while True:\n",
" try:\n",
" # Ask the user for quantity\n",
" quantity = input(f\"Enter quantity for {product}: \")\n",
" \n",
" # Convert input to integer\n",
" quantity = int(quantity)\n",
" \n",
" # Check for negative values\n",
" if quantity < 0:\n",
" raise ValueError(\"Quantity cannot be negative.\")\n",
" \n",
" # Valid quantity, store it and break the loop\n",
" inventory[product] = quantity\n",
" break\n",
" \n",
" except ValueError as e:\n",
" # Handle non-numeric or negative inputs\n",
" print(f\"Invalid input: {e}. Please enter a non-negative integer.\")\n",
" \n",
" return inventory\n",
"\n",
"# Test the function:\n",
"products_list = [\"Apples\", \"Bananas\", \"Oranges\"]\n",
"inventory = initialize_inventory(products_list)\n",
"print(\"Inventory initialized:\", inventory)\n"
]
},
{
"cell_type": "markdown",
"id": "7711e9ff",
"metadata": {},
"source": [
"---\n",
"### STEP 2\n",
"2. Modify the `calculate_total_price` function to include error handling.\n",
" \n",
" - If the user enters an invalid price (e.g., a negative value or a non-numeric value),\n",
" - display an error message and ask them to re-enter the price for that product.\n",
" \n",
" - Use a try-except block to handle the error and continue prompting the user until a valid price is entered."
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "1136ebce",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Invalid input: could not convert string to float: 'a'. Please enter a non-negative number.\n",
"Total price: $45.00\n"
]
}
],
"source": [
"def calculate_total_price(products):\n",
" \"\"\"\n",
" Ask the user to enter the price for each product and calculate the total price.\n",
" Ensures valid, non-negative numeric input.\n",
"\n",
" Args:\n",
" products (list): List of product names.\n",
"\n",
" Returns:\n",
" float: Total price of all products.\n",
" \"\"\"\n",
" total_price = 0.0\n",
" \n",
" for product in products:\n",
" while True:\n",
" try:\n",
" # Ask user for the price\n",
" price = input(f\"Enter price for {product}: \")\n",
" \n",
" # Convert input to float\n",
" price = float(price)\n",
" \n",
" # Check for negative price\n",
" if price < 0:\n",
" raise ValueError(\"Price cannot be negative.\")\n",
" \n",
" # Valid price, add to total and break loop\n",
" total_price += price\n",
" break\n",
" \n",
" except ValueError as e:\n",
" print(f\"Invalid input: {e}. Please enter a non-negative number.\")\n",
" \n",
" return total_price\n",
"\n",
"# Example usage:\n",
"products_list = [\"Apples\", \"Bananas\", \"Oranges\"]\n",
"total = calculate_total_price(products_list)\n",
"print(f\"Total price: ${total:.2f}\")\n"
]
},
{
"cell_type": "markdown",
"id": "63b63ca9",
"metadata": {},
"source": [
"---\n",
"### STEP 3\n",
"3. Modify the `get_customer_orders` function to include error handling.\n",
" - If the user enters an invalid number of orders (e.g., a negative value or a non-numeric value), \n",
" - display an error message and ask them to re-enter the number of orders.\n",
" - If the user enters an invalid product name (e.g., a product name that is not in the inventory), or that doesn't have stock available, \n",
" - display an error message and ask them to re-enter the product name. \n",
" - *Hint*: you will need to pass inventory as a parameter*\n",
" - Use a `try-except` block to handle the error and continue prompting the user until a valid product name is entered.\n"
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "ae63c5c8",
"metadata": {},
"outputs": [],
"source": [
"def get_customer_orders(inventory):\n",
" \"\"\"\n",
" Ask the user for their orders, including quantity and product name.\n",
" Validates:\n",
" - Number of orders (non-negative integer)\n",
" - Product exists in inventory\n",
" - Product has available stock\n",
"\n",
" Args:\n",
" inventory (dict): Dictionary of product names and available quantities\n",
"\n",
" Returns:\n",
" dict: Customer orders with product names and ordered quantities\n",
" \"\"\"\n",
" orders = {}\n",
"\n",
" print(\"\\nEnter your orders:\")\n",
"\n",
" while True:\n",
" try:\n",
" num_orders = input(\"How many different products do you want to order? \")\n",
" num_orders = int(num_orders)\n",
" if num_orders < 0:\n",
" raise ValueError(\"Number of orders cannot be negative.\")\n",
" break\n",
" except ValueError as e:\n",
" print(f\"Invalid input: {e}. Please enter a non-negative integer.\")\n",
"\n",
" for i in range(num_orders):\n",
" while True:\n",
" product_name = input(f\"Enter product name for order #{i+1}: \").strip()\n",
" \n",
" # Check if product exists in inventory\n",
" if product_name not in inventory:\n",
" print(\"Invalid product name. Please choose a product from the inventory.\")\n",
" continue\n",
" \n",
" # Check if product has stock available\n",
" if inventory[product_name] == 0:\n",
" print(f\"Sorry, {product_name} is out of stock. Please choose another product.\")\n",
" continue\n",
" \n",
" # Ask for quantity\n",
" while True:\n",
" try:\n",
" quantity = input(f\"Enter quantity for {product_name}: \")\n",
" quantity = int(quantity)\n",
" if quantity < 0:\n",
" raise ValueError(\"Quantity cannot be negative.\")\n",
" if quantity > inventory[product_name]:\n",
" raise ValueError(f\"Only {inventory[product_name]} units of {product_name} available.\")\n",
" break\n",
" except ValueError as e:\n",
" print(f\"Invalid input: {e}. Please try again.\")\n",
" \n",
" # Save order and reduce inventory\n",
" orders[product_name] = quantity\n",
" inventory[product_name] -= quantity\n",
" break\n",
"\n",
" return orders\n",
"\n",
"# Example usage\n",
"inventory = {\"Apples\": 10, \"Bananas\": 5, \"Oranges\": 8}\n",
"customer_orders = get_customer_orders(inventory)\n",
"print(\"\\nCustomer Orders:\", customer_orders)\n",
"print(\"Updated Inventory:\", inventory)\n"
]
},
{
"cell_type": "markdown",
"id": "f55ac6e6",
"metadata": {},
"source": [
"---\n",
"### STEP 4\n",
"4. Test your code by running the program and deliberately entering invalid quantities and product names. \n",
"- Make sure the error handling mechanism works as expected."
]
},
{
"cell_type": "code",
"execution_count": null,
"id": "e342261e",
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Error: Enter a whole number.\n",
"Error: Enter a whole number.\n",
"Error: Enter a whole number.\n",
"Error: Enter a whole number.\n",
"Error: Enter a whole number.\n",
"Error: Enter a whole number.\n",
"Error: 'ddd' not in inventory. Available: ['Chocolate Bar', 'Truffle Box', 'Candy Cane']\n",
"Error: 'chocolate bar' not in inventory. Available: ['Chocolate Bar', 'Truffle Box', 'Candy Cane']\n",
"Error: 'hehe' not in inventory. Available: ['Chocolate Bar', 'Truffle Box', 'Candy Cane']\n",
"Error: 'aa' not in inventory. Available: ['Chocolate Bar', 'Truffle Box', 'Candy Cane']\n"
]
}
],
"source": [
"def initialize_inventory(products):\n",
" \"\"\"Initialize inventory with error handling for quantities\"\"\"\n",
" inventory = {}\n",
" for product in products:\n",
" while True:\n",
" try:\n",
" quantity = int(input(f\"Enter quantity for {product}: \"))\n",
" if quantity < 0:\n",
" print(\"Error: Quantity cannot be negative.\")\n",
" continue\n",
" inventory[product] = quantity\n",
" break\n",
" except ValueError:\n",
" print(\"Error: Enter a whole number.\")\n",
" return inventory\n",
"\n",
"def get_customer_orders(inventory):\n",
" customer_orders = []\n",
" while True:\n",
" try:\n",
" num_orders = int(input(\"Enter number of orders: \"))\n",
" if num_orders < 0:\n",
" print(\"Error: Number of orders cannot be negative.\")\n",
" continue\n",
" break\n",
" except ValueError:\n",
" print(\"Error: Enter a whole number.\")\n",
" \n",
" for _ in range(num_orders):\n",
" while True:\n",
" product = input(\"Enter product name: \").strip()\n",
" if product not in inventory:\n",
" print(f\"Error: '{product}' not in inventory. Available: {list(inventory.keys())}\")\n",
" continue\n",
" if inventory[product] <= 0:\n",
" print(f\"Error: '{product}' out of stock.\")\n",
" continue\n",
" customer_orders.append(product)\n",
" break\n",
" return customer_orders\n",
"\n",
"def calculate_total_price(products):\n",
" total_price = 0.0\n",
" for product in products:\n",
" while True:\n",
" try:\n",
" price = float(input(f\"Enter price for {product}: $\"))\n",
" if price < 0:\n",
" print(\"Error: Price cannot be negative.\")\n",
" continue\n",
" total_price += price\n",
" break\n",
" except ValueError:\n",
" print(\"Error: Enter numeric value.\")\n",
" return total_price\n",
"\n",
"# Main program\n",
"if __name__ == \"__main__\":\n",
" products = [\"Chocolate Bar\", \"Truffle Box\", \"Candy Cane\"]\n",
" inventory = initialize_inventory(products)\n",
" orders = get_customer_orders(inventory)\n",
" total = calculate_total_price(orders)\n",
" print(f\"\\nFinal order: {orders}\")\n",
" print(f\"Total price: ${total:.2f}\")[conversation_history:6]\n"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3 (ipykernel)",
"display_name": "base",
"language": "python",
"name": "python3"
},
Expand All @@ -90,7 +444,7 @@
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.9.13"
"version": "3.13.9"
}
},
"nbformat": 4,
Expand Down