More Examples of Functions

Here are more examples of functions in Python with clear explanations, step-by-step code, emojis, and practice questions! 🚀

1. Function to Calculate the Square of a Number 🟦

def square(x):
    return x * x

print(square(5))  # Output: 25
print(square(7))  # Output: 49

• You can call square() with any number, and it returns the square!¹

2. Function to Cube a Number 🟩

def cube(x):
    return x ** 3

print(cube(3))  # Output: 27
print(cube(10)) # Output: 1000

• This function raises the input to the power of 3!¹

3. Function with Multiple Parameters ➕

def add(a, b):
    return a + b

print(add(2, 3))  # Output: 5
print(add(10, 20)) # Output: 30

• You can pass two numbers, and it returns their sum!¹²

4. Function Returning Multiple Values 🧑‍🤝‍🧑

def min_and_max(numbers):
    return min(numbers), max(numbers)

smallest, largest = min_and_max([2, 7, 1, 8])
print("Smallest:", smallest)  # Output: Smallest: 1
print("Largest:", largest)    # Output: Largest: 8

• Functions can return more than one value as a tuple!¹

5. Function with No Return (Just Prints) 📢

def greet(name):
    print(f"Hello, {name}!")

greet("Alice")  # Output: Hello, Alice!

• If there is no return, Python returns None by default!¹

6. Function with a Default Parameter Value 🧑‍💻

def power(base, exponent=2):
    return base ** exponent

print(power(3))    # Output: 9 (3 squared)
print(power(3, 3)) # Output: 27 (3 cubed)

• If you don’t provide the second argument, it uses the default!¹

7. Function That Modifies a List (Mutable Argument) 📝

def append_waffles(lst):
    lst.append("Waffles")
    return lst

breakfast = ["Oatmeal", "Eggs", "Pancakes"]
print(append_waffles(breakfast))  # Output: ['Oatmeal', 'Eggs', 'Pancakes', 'Waffles']

• The original list is changed because lists are mutable!¹

8. Recursive Function (Factorial) 🔁

def factorial(n):
    if n == 0:
        return 1
    else:
        return n * factorial(n - 1)

print(factorial(5))  # Output: 120

• The function calls itself to compute the factorial!²

9. Lambda (Anonymous) Function ⚡

double = lambda x: 2 * x
print(double(4))  # Output: 8

• Quick, unnamed function for simple operations!²

10. Function for User Input and Conversion 🧑‍💻

def get_integer(prompt="Enter an integer: "):
    return int(input(prompt))

# Example usage:
# num = get_integer()
# print(num)

• Useful for safely getting numbers from users!²

Practice Questions & Solutions 📝

1️⃣ Write a function that returns the successor of any integer.

def successor(n):
    return n + 1

print(successor(10))  # Output: 11

2️⃣ Write a function that checks if a number is even.

def is_even(n):
    return n % 2 == 0

print(is_even(4))  # Output: True
print(is_even(7))  # Output: False

3️⃣ Write a function that takes a list and returns True if it has an even number of elements.

def is_even_length(lst):
    return len(lst) % 2 == 0

print(is_even_length([1, 2, 3, 4]))  # Output: True
print(is_even_length([1, 2, 3]))     # Output: False

4️⃣ Write a function that takes two numbers and prints their sum (no return).

def print_sum(a, b):
    print(a + b)

print_sum(5, 10)  # Output: 15

5️⃣ Write a function that returns the product of all odd numbers between 1 and n.

def product_of_odds(n):
    product = 1
    for i in range(1, n+1, 2):
        product *= i
    return product

print(product_of_odds(7))  # Output: 105 (1*3*5*7)

Key Points with Emojis 🎯

• Functions can have parameters, return values, or side effects (like printing).
• Functions can return multiple values as tuples.
• Use default arguments to make parameters optional.
• Functions can be recursive (call themselves).
• Lambda functions are quick, unnamed functions for simple tasks.
• Functions help you organize, reuse, and test your code easily!¹²

If you want more advanced examples (like generators, decorators, or closures), just ask! 😃

References: Functions can take arguments, return values, modify mutable objects, be recursive, and can be anonymous (lambda). They are essential for organizing and reusing code efficiently in Python¹².