Python Setup and Your First Program

Setup and Your First Program

Before diving into Python syntax, let's get your development environment ready. All you need is Python installed and a text editor.

Installing Python

Windows

1. Go to https://python.org and click Downloads
2. Download the latest Python version (e.g., 3.13.x)
3. Run the installer — make sure to check "Add Python to PATH"
4. Open Command Prompt (cmd) and verify with python --version

C:\Users\YourName> python --version
Python 3.13.2

Mac

Mac comes with Python 2 (too old), so you need to install Python 3:

1. Go to https://python.org and download the Mac installer
2. Run the installer, or use Homebrew: brew install python3
3. Verify in the terminal: python3 --version

Linux

Most Linux distributions already have Python 3 installed:

# Ubuntu/Debian
sudo apt install python3

# Verify
python3 --version

Hello World Program

Once installed, your first program is always "Hello, World!".

Method 1: Interactive Interpreter

Type python (Windows) or python3 (Mac/Linux) in your terminal to enter interactive mode:

Python 3.13.2 (main, Feb  4 2025, 14:51:09)
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Hello, World!")
Hello, World!
>>> 1 + 2
3
>>> exit()

Method 2: Create a .py File

1. Create a new file called hello.py
2. Enter this code:

print("Hello, World!")

3. Run it from the terminal:

python hello.py

Output:

Hello, World!

Choosing an Editor

You don't need a complex IDE when you're just starting out. Here are some recommendations:

VS Code Setup

1. Download and install VS Code (code.visualstudio.com)
2. Open VS Code, press Ctrl+Shift+X to open the Extensions panel
3. Search for "Python" and install Microsoft's official Python extension
4. Create a new file and save it with a .py extension
5. Right-click in the editor → "Run Python File in Terminal"

Your First Complete Program

Let's put it all together and write a small interactive program:

# First Python program
name = input("What's your name? ")
print("Hello, " + name + "! Welcome to Python!")

When you run it:

What's your name? Alice
Hello, Alice! Welcome to Python!

Common Pitfalls

1. PATH not set (Windows): You MUST check "Add Python to PATH" during installation, otherwise the terminal won't find the python command
2. python vs python3: Windows uses python, Mac/Linux use python3
3. Chinese encoding issues: Python 3 uses UTF-8 by default, so garbled text is rare. If you do run into encoding issues, add # -*- coding: utf-8 -*- at the top of your file

📖 Section Summary

• Download and install Python 3.x from python.org
• On Windows, check "Add Python to PATH" during installation
• Interactive interpreter: type python in the terminal
• .py files: write code in an editor, run with python filename.py
• VS Code + Python extension is the recommended development setup

📝 Homework

1. Install Python and type python --version in the terminal — take a screenshot
2. Write a hello.py file that prints "Hello, World!" and run it successfully
3. In the interactive interpreter, calculate (5 + 3) * 2 and 10 / 3 — observe the results
4. Modify the interactive program above by adding an age variable, and print "Your name is XX, you are XX years old"