Installing Python

You don't have to install Python for this course: the tasks run on our servers, and any code can be executed in the Sandbox. So if you're itching to start — skip ahead, this chapter isn't going anywhere.

But sooner or later you'll want to write code on your own machine: your files, your projects, no browser tab involved. Come back here then — below is the short path from "nothing installed" to "it works" 🚀.

Step 1. Check whether Python is already there

Python may have shipped with your system or been installed earlier — on macOS and Linux it's there almost always. We'll check in the terminal: the window where you type commands as text instead of clicking.

• Windows — press Win, type "PowerShell" and open it.
• macOS — press Cmd + Space, type "Terminal" and open it.
• Linux — usually Ctrl + Alt + T.

Type the command and press Enter:

python3 --version

If a version number comes back — say, Python 3.12.4 — it's already in place and you can skip step 2. Any version starting with a 3 will do.

A "command not found" answer is fine too: it just means Python isn't installed yet. Let's move on.

Step 2. Install Python

Windows

1. Open python.org → Downloads → Windows and download the installer.
2. Run it.
3. On the very first screen tick "Add python.exe to PATH" — and only then click Install Now.
4. Wait for it to finish and close the installer.

That checkbox deserves a word of its own, because it's easy to miss and the consequences are annoying. PATH is the list of folders your system searches for programs when you type a command. Without the tick, Python installs but the system never learns about it: you type python and get "command not found" back. Ticking it takes a second; hunting down the reason afterwards can take half an hour.

If you did miss it, the easiest fix is to run the installer again and choose Modify.

macOS

The first way, with no extra tooling: download the installer from python.org → Downloads → macOS, open the .pkg and follow the steps.

The second way is Homebrew, if you already have it (check with brew -v):

brew install python

Linux

The command depends on your distribution:

• Ubuntu / Debian:

  sudo apt update
  sudo apt install -y python3 python3-pip
  

• Fedora:

  sudo dnf install -y python3 python3-pip
  

• Arch Linux:

  sudo pacman -S python python-pip
  

Step 3. Check that it works

Close the terminal and open it again — it needs to learn about the new program. Now the same command as in step 1:

python3 --version

A version number in reply means you're done, Python is yours.

If Windows still says "command not found", try py --version. If that doesn't help, it's almost certainly the PATH checkbox: run the installer again and choose Modify. Sometimes simply logging out and back in is enough.

On macOS and Linux the command is python3, not python — that's not a fault but the norm: the short name python is historically taken there.

Good luck! ✨