Introduction to Python Programming

1) What is Python?

Python is a high-level, interpreted language. “Interpreted” means you can run Python code without compiling it into a separate executable first. Python focuses on readability and has a clean syntax.

2) Setup: Install Python & choose an editor

Option A: Install on Windows / macOS / Linux

1. Download Python from the official site (see Links).
2. On Windows: during install, tick “Add Python to PATH”.
3. Verify in terminal/command prompt:

   python --version
   
   pip --version

Option B: Start online (no installation)

Use the Pyodide editor below to run Python directly in your browser.

Recommended editor

3) Your first Python program

Create a file named hello.py and write:

print("Hello, World!")

Run it in terminal:

python hello.py

4) Python basics you must know

4.1 Variables (store data)

name = "Champak"

age = 20 pi = 3.14159 is_student = True

4.2 Data types (common ones)

# String

city = "Varanasi"

Integer and Float

count = 10 price = 99.50

Boolean

is_open = False

List (ordered, changeable)

nums = [1, 2, 3]

Tuple (ordered, not changeable)

point = (10, 20)

Dictionary (key-value)

student = {"name": "Asha", "marks": 92}

Set (unique items)

unique = {1, 2, 2, 3}  # becomes {1, 2, 3}

4.3 Input and output

name = input("Enter your name: ")

print("Hello,", name)

4.4 Conditions (if / elif / else)

marks = 72

if marks >= 90: print("Grade: A") elif marks >= 75: print("Grade: B") else: print("Grade: C")

4.5 Loops (repeat work)

# for loop

for i in range(5): print(i)

while loop

n = 3 while n > 0: print("Countdown:", n) n -= 1

4.6 Functions (reuse code)

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

result = add(3, 4) print(result)

4.7 Imports (use libraries)

import math

print(math.sqrt(81))

5) Packages, pip, and virtual environments

Python has a package manager called pip. Install packages like this:

pip install requests

Create a virtual environment

# create venv

python -m venv .venv

activate (Windows)

.venv\Scripts\activate

activate (macOS/Linux)

source .venv/bin/activate

Then install packages inside it

pip install requests

6) Mini practice (do these today)

1. Print your name and age in one line.
2. Take two numbers as input and print their sum.
3. Check if a number is even or odd.
4. Print numbers 1 to 20 using a for loop.
5. Make a function that returns the square of a number.

7) Pyodide Python Editor (Run Python in Browser)

Click Load Pyodide first. If you opened the page as file:///, use a local server (VS Code Live Server) or host the page.

Output will appear here…

8) What to learn next

• Strings and string methods
• Lists, tuples, sets, dictionaries (more deeply)
• File handling (read/write files)
• Errors and exceptions (try/except)
• OOP (classes and objects)
• Modules, packages, and project structure