⭐ Python Modules

A module in Python is simply a file that contains Python code — such as variables, functions, classes, and runnable code — that can be imported and reused in other Python programs.

A module helps in organizing large programs into small, manageable, and reusable code blocks.

⭐ Module Definition

A module is a Python file (.py) that contains definitions of functions, variables, and classes which can be reused in other programs.

In simple words:

👉 Module = A file containing Python code that can be imported
👉 Extension = .py
👉 Used for code reusability + modularity

⭐ Why Use Modules?

✔ Reusability of code
✔ Organize code into logical parts
✔ Avoid rewriting commonly used logic
✔ Easier to maintain large programs
✔ Provides namespaces (avoids name conflicts)
✔ Allows use of thousands of Python’s built-in modules

⭐ Examples of Modules in Python

Python comes with many built-in modules:

Module	Purpose
`math`	Mathematical functions
`random`	Random number generation
`datetime`	Date & time operations
`os`	Operating system interaction
`sys`	System-specific parameters
`statistics`	Statistical operations

⭐ Creating Your Own Module

Create a file named mymodule.py:

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

x = 100

Now import it in another Python file:

import mymodule

print(mymodule.greet("John"))
print(mymodule.x)

⭐ Importing Modules

Python provides many ways to import modules:

✔ 1. Basic import

import math

✔ 2. Import with alias

import math as m
print(m.sqrt(16))

✔ 3. Import specific functions

from math import sqrt, pi

✔ 4. Import all (not recommended)

from math import *

⭐ Module Search Path

When importing, Python looks for a module in:

Current working directory
Built-in modules
Installed modules (site-packages)
System environment paths

You can check this with:

import sys
print(sys.path)

⭐ Types of Modules

1. Built-in Modules

Provided with Python installation
Example: math, os, random

2. User-defined Modules

Modules written by the programmer

3. Third-party Modules

Installed using pip
Example: numpy, pandas, requests

⭐ Advantages of Modules

✔ Improves code reusability
✔ Keeps code organized
✔ Reduces program size
✔ Easy to debug and maintain
✔ Encourages modular programming
✔ Provides namespaces

⭐ Example Program Using Modules

Program using the math module:

import math

print(math.sqrt(25))
print(math.factorial(5))
print(math.pi)

⭐ Exam-ready Definition (Short)

A module in Python is a file containing Python definitions and statements.
It helps in organizing code logically and allows reuse of functions, variables, and classes by importing into other programs.

Python Modules: Module definition