Lesson 16: Python Modules, Packages, and Pip | Coding Class Series

Introduction

Welcome to Lesson 16!
In this lesson, we will learn about Python modules and packages, how to import them, and how to install external libraries using pip.
Modules and packages help you organize code and reuse functionality efficiently.

1. What is a Module?

A module is a file containing Python code (functions, classes, variables).
You can reuse modules in multiple programs.

Example: math module

import math

print(math.sqrt(16))  # Output: 4.0
print(math.pi)        # Output: 3.141592653589793

2. Importing Modules

You can import a module in different ways:

# Import the whole module
import math
print(math.factorial(5))  # Output: 120

# Import specific functions
from math import factorial, ceil
print(factorial(6))  # Output: 720
print(ceil(4.2))     # Output: 5

# Import with alias
import math as m
print(m.sqrt(25))    # Output: 5.0

3. Creating Your Own Module

You can create a module by saving functions in a .py file.

my_module.py

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

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

main.py

import my_module

print(my_module.greet("Alice"))
print(my_module.add(10, 5))

4. What is a Package?

A package is a folder containing multiple modules and an __init__.py file.
It allows better organization of related modules.

Example structure:

my_package/
    __init__.py
    module1.py
    module2.py

Usage:

from my_package import module1
module1.function_name()

5. Installing External Libraries with pip

pip is the Python package manager. You can install external libraries easily.

# Install a library
pip install requests

# Check installed libraries
pip list

Example usage:

import requests

response = requests.get("https://api.github.com")
print(response.status_code)  # Output: 200

6. Upgrading and Uninstalling Packages

# Upgrade a package
pip install --upgrade requests

# Uninstall a package
pip uninstall requests

7. Practice Exercises

1. Create a module calculator.py with functions for addition, subtraction, multiplication, and division. Import it in another program.
2. Organize two modules (math_ops.py and string_ops.py) into a package my_utils. Import and use functions.
3. Install the numpy library using pip and create an array.
4. Upgrade numpy and then uninstall it using pip commands.

Lesson 10: Python Modules and Libraries | Coding Class Series

Introduction

Welcome to Lesson 10!
In this lesson, we will learn about Python Modules and Libraries. These are essential for reusing code, extending Python functionality, and making development faster and easier.

1. What is a Module?

A module is a Python file (.py) that contains functions, classes, and variables which you can use in other Python programs.

Example:

# math_module.py
def add(a, b):
    return a + b

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

You can use this module in another file using import:

import math_module

print(math_module.add(10, 5))       # Output: 15
print(math_module.subtract(10, 5))  # Output: 5

2. Built-in Python Modules

Python has many built-in modules ready to use:

• math → Mathematical functions
• random → Random number generation
• datetime → Date and time functions
• os → Operating system functionalities

Example:

import math
import random
from datetime import datetime

print(math.sqrt(25))          # Output: 5.0
print(random.randint(1, 10))  # Output: Random number between 1 and 10
print(datetime.now())         # Output: Current date and time

3. Installing Third-Party Libraries

Python libraries like requests, numpy, pandas, etc., can be installed using pip:

pip install requests
pip install numpy

Example using requests:

import requests

response = requests.get("https://api.github.com")
print(response.status_code)  # Output: 200

4. Creating Your Own Library

You can combine multiple modules into a package (your own library):

my_library/
│
├── __init__.py
├── math_utils.py
└── string_utils.py

Usage:

from my_library.math_utils import add
print(add(5, 10))  # Output: 15

5. Practice Exercises

1. Create a module calc.py with functions multiply and divide. Import it in another file and test it.
2. Use the random module to generate a random list of numbers and find the max and min.
3. Install requests and fetch data from any public API.
4. Create a simple package with 2 modules and use it in a program.