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4. Setting up IDLE

1. Introduction​

IDLE (Integrated Development and Learning Environment) is Python’s simple built-in editor.
It is included with most Python installations and is a great starting point for beginners.

2. Checking if IDLE is Installed​

Open a terminal (macOS/Linux) or Command Prompt (Windows) and type:

idle3
  • If IDLE opens, you are ready to use it.
  • If the command is not found, install it using your package manager.

3. Installing IDLE on Windows​

  • IDLE is automatically installed when you install Python from python.org.
  • If you unchecked IDLE during installation, run the installer again and enable the tcl/tk and IDLE option.

4. Installing IDLE on macOS​

  • If you installed Python using the official .pkg installer, IDLE is already included.
  • If using Homebrew, install IDLE with:
brew install python-tk

5. Installing IDLE on Linux​

For Ubuntu/Debian:

sudo apt update
sudo apt install idle3 -y

For Fedora:

sudo dnf install python3-tools -y

For Arch:

sudo pacman -S tk

6. Starting IDLE​

  • On Windows: search for IDLE in the Start Menu.
  • On macOS/Linux: run idle3 from Terminal.

When IDLE opens, you will see the Python Shell (interactive REPL).

7. Running Your First Program​

  1. In IDLE, go to File → New File.
  2. Type this program:
print("Hello, Python from IDLE!")
  1. Save the file as hello.py.
  2. Press F5 or choose Run → Run Module.
  3. You should see the output in the Python Shell window:
Hello, Python from IDLE!

8. Customizing IDLE​

  • Fonts and Colors: Go to Options → Configure IDLE.
  • Themes: Switch to dark mode or change syntax colors.
  • Indentation: Adjust spaces per tab for coding style.

9. Troubleshooting​

  • IDLE not opening: Ensure tkinter is installed.
    On Ubuntu/Debian:

    sudo apt install python3-tk -y

  • Multiple Python versions: If IDLE opens the wrong version, check the shebang in the IDLE launcher or use the full command:

idle3.12

10. Next Steps​

✅ You now have IDLE set up and running.
In the next chapter, we will set up VS Code, a more powerful editor for Python development.