Python Modules and Packages

As your Python programs grow larger and more complex, organizing your code becomes essential. Python provides two key mechanisms for this: modules and packages. These allow you to break down your code into smaller, manageable, and reusable components.

Modules: The Building Blocks

A module in Python is simply a file containing Python code. It can define functions, classes, and variables that you can use in other Python programs.

1# math_operations.py
2
3def add(a, b):
4    """Add two numbers and return the result."""
5    return a + b
6
7def subtract(a, b):
8    """Subtract b from a and return the result."""
9    return a - b
10
11# A constant
12PI = 3.14159
13
14def calculate_circle_area(radius):
15    """Calculate the area of a circle with the given radius."""
16    return PI * radius * radius

Using a Module

You can use a module in your program by importing it with the import statement:

1# Import the entire module
2import math_operations
3
4# Now we can use functions from the module
5result = math_operations.add(10, 5)
6print(f"10 + 5 = {result}")
7
8# We can also access constants
9print(f"The value of PI is: {math_operations.PI}")

Python Packages

A package is a way of organizing related modules into a directory hierarchy. It's simply a directory that contains Python modules and a special __init__.py file.

Modules and packages are powerful tools for organizing Python code that help you build maintainable and reusable software.