Modules and Packages in Python- Python Course

Modules and Packages

Importing Standard Modules in Python

Python comes with a rich collection of standard modules that can be imported directly, without installation. These provide useful functionalities for math, data, files, system operations, and more.

Simple Import

import math
import datetime

Import with Alias

import math as m
print(m.sqrt(16))   # Displays: 4.0

Partial Import

from datetime import date
print(date.today())   # Displays: current date

Creating Your Own Modules in Python

A module is a Python file containing functions, classes, or variables that can be reused in other files. Creating your own modules helps organize code and separate logic into clear components.

Creating a Module

# File: salut.py
def salut(name):
    return f"Hello, {name}!"

Importing the Module

# Main file: main.py
import salut

print(salut.salut("John"))   # Displays: Hello, John!

Selective Import

from salut import salut
print(salut("Anna"))   # Displays: Hello, Anna!

Python Standard Library: math - random - datetime - os

The Python standard library provides powerful modules for mathematical operations, random generation, date/time manipulation, and file system interaction.

math - Mathematical Functions

import math

print(math.sqrt(25))     # Displays: 5.0
print(math.pi)           # Displays: 3.141592653589793

random - Random Generation

import random

print(random.randint(1, 10))     # Integer between 1 and 10
print(random.choice(["red", "green", "blue"]))   # Random element from list

datetime - Working with Dates and Times

from datetime import datetime

now = datetime.now()
print(now.strftime("%d-%m-%Y %H:%M"))   # Displays current date and time

os - File System Interaction

import os

print(os.getcwd())       # Displays current directory
print(os.listdir())      # Lists files in directory

Installing Packages with pip

pip is the official package manager for Python. It allows you to install external libraries from the Python Package Index (PyPI) and integrate them into your projects.

Installing a Package

pip install requests

Checking Installed Packages

pip list

Updating a Package

pip install --upgrade requests

Uninstalling a Package

pip uninstall requests

Structure of a Python Package

A Python package is a directory containing one or more modules and a special file __init__.py. Packages allow organizing code logically and reusing components.

Basic Structure

project/
├── util/
│   ├── __init__.py
│   ├── calc.py
│   └── text.py
├── main.py

Importing from a Package

# File: main.py
from util.calc import add
from util.text import uppercase

The __init__.py File

# File: util/__init__.py
# Can be empty or expose common functions

Using venv for Virtual Environments in Python

venv is Python's standard module for creating virtual environments. They allow isolation of packages and dependencies per project, avoiding version conflicts.

Creating a Virtual Environment

python -m venv env

Activating the Environment

# Windows
env\Scripts\activate

# macOS / Linux
source env/bin/activate

Deactivating the Environment

deactivate

Installing Packages in the Environment

pip install flask

🧠 Quiz - Modules and Packages in Python