Section 2: Functions and Modules

Lesson 1: Defining Functions

1.1 Creating Functions with Parameters and Return Values

Functions in Python allow you to encapsulate code for reuse. They can have parameters and return values.

Example: 

# Function with parameters and return value

def greet(name):

    return "Hello, " + name + "!"

# Calling the function

result = greet("Alice")

print(result)

1.2 Scope of Variables

The scope of a variable defines where it can be accessed. Local variables are confined to the function they are defined in, while global variables are accessible throughout the entire script.

Example:

# Global variable

global_variable = "I am global"

# Function with local variable

def local_function():

    local_variable = "I am local"

    print(global_variable)  # Accessing global variable

    print(local_variable)   # Accessing local variable

# Calling the function

local_function()

print(global_variable)  # Global variable is accessible here

Lesson 2: Working with Modules

2.1 Introduction to Python Modules

Modules in Python are files containing Python code. They allow you to organize code into reusable units.

Example: 

# Example module saved as mymodule.py

def add(a, b):

    return a + b

def multiply(a, b):

    return a * b

2.2 Importing and Using Modules

You can import modules in Python to use their functions and variables.

Example: 

# Importing the module

import mymodule

# Using functions from the module

result_add = mymodule.add(5, 3)

result_multiply = mymodule.multiply(2, 4)

print("Addition Result:", result_add)

print("Multiplication Result:", result_multiply)

Alternatively, you can import specific functions or variables from a module.

Example:

# Importing specific functions

from mymodule import add, multiply

# Using the imported functions

result_add = add(5, 3)

result_multiply = multiply(2, 4)

print("Addition Result:", result_add)

print("Multiplication Result:", result_multiply)

In Section 2, we explored functions and modules in Python. Functions provide a way to encapsulate and reuse code, supporting parameters and return values. Understanding variable scope is crucial for managing data within and outside functions.

Modules, as reusable units of code, promote code organization and maintainability. Importing modules allows us to leverage their functions and variables in our scripts. As you incorporate functions and modules into your Python programming, you'll enhance code modularity, readability, and reusability. These concepts are foundational for building scalable and well-organized Python projects.