Python Loops

# Python Loops - Interactive Examples
# Learn for loops, range(), and iteration through hands-on practice
# === PATTERN GENERATOR ===
# Example of nested loops and range() usage
rows = 5
pattern_type = "stars"
if pattern_type == "stars":
    for i in range(1, rows + 1):
        print("*" * i)
elif pattern_type == "numbers":
    for i in range(1, rows + 1):
        for j in range(1, i + 1):
            print(j, end=" ")
        print()  # New line
elif pattern_type == "pyramid":
    for i in range(1, rows + 1):
        spaces = " " * (rows - i)
        stars = "*" * (2 * i - 1)
        print(spaces + stars)
# === DATA PROCESSOR ===
# Example of list comprehensions and iteration
input_data = [1, 2, 3, 4, 5]
operation = "double"
if operation == "double":
    result = [x * 2 for x in input_data]
elif operation == "square":
    result = [x ** 2 for x in input_data]
elif operation == "filter_even":
    result = [x for x in input_data if x % 2 == 0]
elif operation == "sum":
    total = 0
    for number in input_data:
        total += number
    result = total
print(f"Operation: {operation}")
print(f"Input: {input_data}")
print(f"Result: {result}")
# === SHOPPING CART CALCULATOR ===
# Example of iterating through complex data structures
shopping_cart = [
    {"name": "Laptop", "price": 999.99, "quantity": 1},
    {"name": "Mouse", "price": 29.99, "quantity": 2},
    {"name": "Keyboard", "price": 79.99, "quantity": 1}
]
# Calculate subtotal
subtotal = 0
for item in shopping_cart:
    item_total = item["price"] * item["quantity"]
    subtotal += item_total
    print(f"{item['name']}: ${item['price']:.2f} x {item['quantity']} = ${item_total:.2f}")
# Apply discount if subtotal > $500
discount = subtotal * 0.1 if subtotal > 500 else 0
total = subtotal - discount
print(f"\nSubtotal: ${subtotal:.2f}")
print(f"Discount: ${discount:.2f}")
print(f"Total: ${total:.2f}")
# Key Loop Concepts:
# - for loops with range(start, stop, step)
# - Iterating through lists, strings, and dictionaries
# - List comprehensions for concise transformations
# - Nested loops for complex patterns
# - enumerate() for index and value pairs
# - Breaking down complex problems into iterations