Introduction to Python

What is Python?

Python is a high-level, general-purpose programming language created by Guido van Rossum in 1991. It is known for clean, English-like syntax that is easy to read and write — which is why it is the recommended first language in CBSE Class 11/12 and most B.Tech courses.

Why Python is So Popular

• Simple syntax — reads almost like English.
• Beginner-friendly — no semicolons, no type declarations.
• Huge libraries — NumPy, Pandas, Django, TensorFlow ready to use.
• Cross-platform — same code runs on Windows, Linux, Mac.
• In demand — used in AI, data science, web and automation jobs.

Where Python is Used

Program 1: Your First Line

print("Hello, I am learning Python!")

• print() is a built-in function that shows text on screen.
• The text inside quotes is a string.
• No semicolon needed at the end — Python uses the line break.

Program 2: A Tiny Calculator

a = 10
b = 5
print("Sum     :", a + b)
print("Diff    :", a - b)
print("Product :", a * b)
print("Divide  :", a / b)

• Variables a and b hold numbers.
• + - * / are arithmetic operators.
• Notice / gives 2.0 (a float) — Python division always returns a decimal.

Key Features

• Interpreted — runs line by line, no separate compile step.
• Dynamically typed — no need to declare variable types.
• Object-oriented — supports classes and objects.
• Free & open-source.

Short History

Python was created by Guido van Rossum and released in 1991. The name comes from the comedy group "Monty Python", not the snake. Python 3 (released 2008) is the modern version used today.

Common Mistakes

• Installing/using old Python 2 instead of Python 3.
• Forgetting quotes around text in print().
• Mixing tabs and spaces for indentation.

Practice Tasks

1. Print your name and class on two separate lines.
2. Store two numbers and print all four arithmetic results.
3. Print a small paragraph about why you want to learn Python.

Summary

• Python is a simple, high-level, interpreted language.
• Used in AI, data science, web and automation.
• print() displays output; no semicolons needed.
• Always use Python 3.