Lab Activity: Functions and Code Organisation

Objective

By the end of this lab, you will be able to:

• Define and call functions.

• Use different types of function arguments.

• Return values from functions.

• Understand local vs global variables.

• Write and use lambda functions.

• Organize code into modules.

• Add documentation using docstrings and type hints.

step-by-step instructions:

 Step 1: Defining and Calling Functions

Activity: Write your first function.

# Define a simple function
def greet():
    print("Hello, welcome to Python functions!")

# Call the function
greet()

Expected Output:

Hello, welcome to Python functions!

 Step 2: Function Arguments

Activity: Practice with positional, keyword, default, and variable-length arguments.

# Positional arguments
def add(a, b):
    print("Sum is:", a + b)

add(3, 5)   # Positional

# Keyword arguments
def introduce(name, age):
    print(f"My name is {name} and I am {age} years old.")

introduce(age=20, name="Sara")

# Default arguments
def greet_user(name="Guest"):
    print("Hello", name)

greet_user()
greet_user("Ali")

# Variable-length arguments (*args)
def multiply_all(*numbers):
    result = 1
    for n in numbers:
        result *= n
    print("Multiplication result:", result)

multiply_all(2, 3, 4)

Expected Output:

Sum is: 8
My name is Sara and I am 20 years old.
Hello Guest
Hello Ali
Multiplication result: 24

 Step 3: Return Values

Activity: Functions that return a value.

def square(number):
    return number * number

result = square(6)
print("Square is:", result)

Expected Output:

Square is: 36

Step 4: Variable Scope

Activity: Local vs Global variables.

x = 10   # Global variable

def show_number():
    x = 5   # Local variable
    print("Inside function:", x)

show_number()
print("Outside function:", x)

Expected Output:

Inside function: 5
Outside function: 10

Step 5: Lambda Functions

Activity: Write short anonymous functions.

# Normal function
def double(n):
    return n * 2

# Lambda function
double_lambda = lambda n: n * 2

print(double(4))
print(double_lambda(4))

Expected Output:

8
8

 Step 6: Organizing Code into Modules

Activity: Create your own module.

1. Create a file called mymath.py with this code:

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

2. Create another file main.py:

   import mymath
   
   print("Addition:", mymath.add(10, 5))
   print("Subtraction:", mymath.subtract(10, 5))
   

Expected Output:

Addition: 15
Subtraction: 5

 Step 7: Docstrings and Type Hints

Activity: Document your function.

def greet_user(name: str) -> str:
    """
    Function to greet a user.
    
    Parameters:
    name (str): The name of the user
    
    Returns:
    str: Greeting message
    """
    return f"Hello, {name}!"

print(greet_user("Aisha"))

Expected Output:

Hello, Aisha!

Lab Tasks for Students

1. Write a function is_even(number) that returns True if the number is even, otherwise False.

2. Create a function that accepts any number of names (*args) and prints them one by one.

3. Write a module greetings.py with a function say_goodbye(name) and import it into another script.