Lesson 1: Introduction to Python

🎯 Lesson Objective

By the end of this lesson, you’ll understand:

What Python is and where it’s used
How to install and run Python
Basic syntax, keywords, and comments
Writing and running your first Python program

📘 1. What is Python?

Python is a high-level, interpreted programming language known for:

Simple and readable syntax
Wide use in web development, data science, automation, and AI
Huge community and open-source support

Created by: Guido van Rossum (in 1991)
Current versions: Python 3.x (Python 3.12 is latest as of 2025)

💡 2. Why Learn Python?

Reason	Description
🧠 Easy to Learn	Clean syntax, beginner-friendly
⚙️ Versatile	Used in data science, AI, web, scripting
📊 Libraries	Supports powerful tools like NumPy, Pandas, Django
💼 Career	In-demand skill in IT, automation, analytics

⚙️ 3. Setting Up Python

Step 1: Download from https://www.python.org/downloads/
Step 2: Check the box “Add Python to PATH” during installation.
Step 3: Verify installation:

python --version

Output Example:

Python 3.12.2

Step 4: Open an IDE (like VS Code, PyCharm, or IDLE) to start coding.

🧩 4. Your First Python Program

Let’s print your first message 👇

# My first Python program
print("Hello, Python World!")

Output:

Hello, Python World!

🧠 5. Understanding Python Syntax

Concept	Example	Description
Case Sensitive	`Name` ≠ `name`	Python differentiates between uppercase and lowercase
Indentation	`if True:` `print("Yes")`	Uses spaces (not braces) to define code blocks
Comments	`# This is a comment`	Comments are ignored by Python interpreter
Multiline Comment	`''' comment '''`	Used for longer notes or documentation

📊 6. Python Keywords

Reserved words used by Python — you can’t use them as variable names.

Examples:

and, as, assert, break, class, continue, def, del, elif,
else, except, False, finally, for, from, global, if,
import, in, is, lambda, None, not, or, pass, raise,
return, True, try, while, with, yield

Try viewing all Python keywords:

import keyword
print(keyword.kwlist)

💻 7. Interactive Example: Simple Calculator

# Simple addition program
num1 = int(input("Enter first number: "))
num2 = int(input("Enter second number: "))

result = num1 + num2
print("The sum is:", result)

Example Output:

Enter first number: 10
Enter second number: 5
The sum is: 15

🧪 8. Practice Tasks

✅ Task 1: Write a program to print your name and favorite hobby.
✅ Task 2: Write a Python program that prints:

Welcome to Python Programming!

✅ Task 3: Write a Python program to perform subtraction of two numbers given by the user.
✅ Task 4: Add a comment above each line explaining what it does.

🧱 9. Summary

Topic	Description
Language Type	Interpreted, high-level
Key Function	`print()`
Code Block	Defined by indentation
Comments	`# single line`, `''' multi-line '''`
First Step	Install and verify Python 3

🏁 10. Assignment (Mini Project)

Project: “Personal Info Display”
Write a small Python script that prints:

Your name
Your favorite language
Your goal for learning Python