Lesson 4: Functional Programming - Student In-Class Practices

In-Class Practice 1: Lambda Functions Practice

Scenario

You're helping an online store manage their product inventory using Python. Your task is to use lambda functions to sort, categorize, and analyze product data efficiently.

The Dataset

products = [
    {'name': 'Wireless Headphones', 'price': 89.99, 'category': 'Electronics', 'stock': 45},
    {'name': 'Coffee Maker', 'price': 129.99, 'category': 'Appliances', 'stock': 12},
    {'name': 'Running Shoes', 'price': 79.99, 'category': 'Sports', 'stock': 23},
    {'name': 'Bluetooth Speaker', 'price': 59.99, 'category': 'Electronics', 'stock': 67},
    {'name': 'Yoga Mat', 'price': 24.99, 'category': 'Sports', 'stock': 8}
]

Task 1: Basic Lambda Sorting

Use lambda functions to sort the product data in different ways:

# TODO: Sort products by price (highest first)
by_price = sorted(products, key=# YOUR CODE HERE)

# TODO: Sort products by category, then by name alphabetically
by_category_name = sorted(products, key=# YOUR CODE HERE)

# Test your sorting
print("Most expensive:", by_price[0]['name'])
print("First alphabetically:", by_category_name[0]['name'])

Task 2: Lambda Conditions

Create lambda functions that make decisions based on product data:

# TODO: Create a lambda to determine price category
# - Price >= 100: 'Premium'
# - Price <= 50: 'Budget'  
# - Otherwise: 'Standard'
price_category = lambda price: # YOUR CODE HERE

# TODO: Create a lambda to check stock status
# - Stock <= 10: 'Low Stock'
# - Otherwise: 'In Stock'
stock_status = lambda stock: # YOUR CODE HERE

# Test your lambdas
print("Product Status Report:")
for product in products:
    category = price_category(product['price'])
    status = stock_status(product['stock'])
    print(f"{product['name']}: {category}, {status}")

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In-Class Practice 2: Map Function with Employee Salaries

Scenario

The HR department needs your help calculating salary adjustments for all employees. You'll use the map() function with lambda expressions to process employee data efficiently.

The Dataset

employees = [
    {'name': 'Alice Johnson', 'job': 'Developer', 'salary': 75000},
    {'name': 'Bob Smith', 'job': 'Designer', 'salary': 65000},
    {'name': 'Carol Davis', 'job': 'Manager', 'salary': 85000},
    {'name': 'David Wilson', 'job': 'Analyst', 'salary': 55000},
    {'name': 'Emma Brown', 'job': 'Developer', 'salary': 72000}
]

Task: Salary Increase Calculation

The company is giving all employees a 7% raise. Use map() with a lambda function to create updated employee records with the new salaries.

# TODO: Use map() with lambda to create new employee dicts with 7% salary raise
updated_employees = list(map(# YOUR CODE HERE, employees))

# Test your result
print("Original employees:")
for emp in employees:
    print(f"  {emp['name']} ({emp['job']}): ${emp['salary']:,}")

print("\nAfter 7% raise:")
for emp in updated_employees:
    print(f"  {emp['name']} ({emp['job']}): ${emp['salary']:,.2f}")

In-Class Practice 3: Filter Function with Book Data

Scenario

You're helping a library system filter their book collection. You'll use the filter() function with lambda expressions to find books that meet specific criteria.

The Dataset

books = [
    {'title': 'Python Programming', 'pages': 320, 'rating': 4.5, 'available': True},
    {'title': 'Web Development', 'pages': 450, 'rating': 3.8, 'available': False},
    {'title': 'Data Science', 'pages': 280, 'rating': 4.9, 'available': True},
    {'title': 'Machine Learning', 'pages': 520, 'rating': 4.2, 'available': True},
    {'title': 'JavaScript Basics', 'pages': 180, 'rating': 3.5, 'available': False}
]

Task: Find High-Quality Available Books

Find all books that are available AND have a rating of 4.0 or higher using filter() with a lambda function.

# TODO: Use filter() with lambda to find available books with rating >= 4.0
quality_books = list(filter(# YOUR CODE HERE, books))

# Test your result
print("High-quality available books:")
for book in quality_books:
    print(f"  {book['title']} - Rating: {book['rating']}")