Introduction

In this lesson, you'll transition from learning about Python to actively running Python code on your computer. You will:

• Install Python on Windows, macOS, and Linux using official sources
• Configure environment variables so you can run python from any terminal
• Verify your installation using simple commands and a test script
• Compare popular IDEs and editors for Python
• Set up and customize an IDE, focusing on VS Code and PyCharm
• Install and manage essential tools: pip, virtual environments, and package managers

By the end of this lesson, your system will be ready for hands-on coding throughout the course.

Installing Python on Different Operating Systems

We prioritize official distributions to avoid broken or outdated installations.

Windows

1. Visit the official download page: Python for Windows
2. Download the latest stable Python 3.x installer (64-bit).
3. Run the installer, making sure to:
   • Check Add Python 3.x to PATH (this is crucial).
4. Choose Customize installation if you prefer, but default options are safe.
5. Complete the installation process.

macOS

macOS comes with a system Python that's often outdated and reserved for the OS. Install your own version:

1. Visit Python for macOS
2. Download the latest macOS 64-bit universal2 installer.
3. Open the .pkg file and follow the installation wizard.
4. Post-installation, Python is usually available as python3 and pip3.

Note: You can also use Homebrew (brew install python), but we'll assume you use the official installer unless otherwise specified.

Linux (Ubuntu / Debian-based and Others)

Most Linux distributions include Python, but you might need development-friendly versions.

• Check existing Python:

  python3 --version
  

• Ubuntu / Debian install or update:

  sudo apt update
  sudo apt install python3 python3-pip
  

• Fedora / RHEL:

  sudo dnf install python3 python3-pip
  

Configuring Environment Variables and Verifying Installation

Checking Python from the Command Line

Open a terminal (Command Prompt / PowerShell on Windows, Terminal on macOS/Linux) and run:

python --version

If that fails (commonly on macOS/Linux), try:

python3 --version

You should see something like:

Python 3.12.1

Fixing PATH on Windows (if needed)

If python is not recognized:

1. Know the exact location where Python installed
2. Press Win key, search for Environment Variables.
3. Open Edit the system environment variables → Environment Variables….
4. Under User variables, select Path → Edit.
5. Add entries similar to below or you location where python installed:
   • C:\Users\<YourUser>\AppData\Local\Programs\Python\Python312\
   • C:\Users\<YourUser>\AppData\Local\Programs\Python\Python312\Scripts\
6. Click OK on all dialogs, restart your terminal, and run python --version again.

Running a Simple Test Script

Create a file named test_setup.py and add:

import sys

print("Python is working!")
print("Version:", sys.version)
print("Executable:", sys.executable)

Run it from the terminal in the folder where the file is saved:

python test_setup.py

Expected output:

Python is working!
Version: 3.12.1 (tags/...) 
Executable: C:\Users\YourUser\AppData\Local\Programs\Python\Python312\python.exe

This confirms Python runs correctly and shows which interpreter you are using.

Summary / Key Takeaways

In this lesson, you have learned how to:

• Install Python from official sources on Windows, macOS, and Linux to avoid outdated system versions.
• Configure and verify your Python installation using PATH settings and test scripts from the command line.
• Confirm Python is working correctly by creating and running small test programs from both the terminal and IDE.