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Install Python

Getting Python working is the only setup step before any course — no experience needed.

What is Python?

Python is a general-purpose programming language created back in 1991 by Guido van Rossum. I've always found it to be wonderfully user-friendly — something people with and without a technical background can pick up. It's grown exponentially from its early days into an enterprise-capable tool that fuels everything from personal hobbies to the highly complex systems running inside public and private institutions alike.

I like to use Python to teach computer science for a few reasons:

  • Familiarity: it's one of the first languages I learned (Java and Python, both back in 2012)... so naturally I fell for Python and divorced Java. 😅
  • Readability: Python makes you use whitespace and indentation, which keeps your code readable — for you and for everyone who reads it after you. (Java will happily let you cram a 1,000-line program onto a single line and it'll technically "work"... but no one will like you for it.)
  • Low learning curve: you don't need to know the nitty-gritty of how computers work to start. Those details help later, as we move into moderate and advanced topics — but whether you're here for an elective credit, because you're bored, or because you want to build something fun like your own Raspberry Pi home thermometer1, Python meets you right where you are.

I hope you'll come to like it for these reasons — or for reasons all your own.

The full, maintained walk-through (macOS, Windows, Linux), an editor recommendation, a one-command environment check, and troubleshooting lives in the Computer Science 1 course repository, kept current there so there's a single source of truth:

Module 0 — Set up Python

The short version

  1. Download the current Python from python.org/downloads (the big yellow button) — not an older release.
  2. Windows: check "Add python.exe to PATH" during install. macOS/Linux: use the python3 command.
  3. Start in IDLE (it ships with Python) — it keeps you focused on concepts instead of leaning on autocomplete.
  4. Verify: run python3 --version (or python --version on Windows). Any 3.13+ is ideal.

You don't need virtual environments or pyenv for an intro course — see the Module 0 setup guide for why (and how, if you want them anyway).

Meet IDLE — the shell and the editor

When you open IDLE, you're actually meeting two tools that work together. Knowing which is which will save you a lot of early confusion, so let's take two minutes here.

The interactive shell (the >>> window)

The first window you see is the interactive shell. It's a place where you type one line, press Enter, and Python answers right away — a bit like a calculator, or a quick back-and-forth conversation. That >>> is Python's prompt; you don't type it, you just type after it.

>>> 2 + 2
4
>>> name = "Dakota"
>>> name
'Dakota'

Type a value and it echoes back. Store something in a name and Python quietly remembers it. The shell is perfect for quick experiments — "wait, what does this do?" — and you'll lean on it constantly. The one catch: it forgets everything the moment you close it.

The editor (where real programs live)

When you want to keep your steps and run them again later, you write them in a file using IDLE's editor. Open it with File → New File, type your program, save it with a name ending in .py (like first_program.py), and run it with Run → Run Module (or just F5).

One thing that trips people up: a saved file doesn't echo values back the way the shell does. In the shell, typing name shows you 'Dakota'; in a file, nothing appears unless you ask for it with print(...). That's not a bug — it's the difference between a conversation (the shell) and a written recipe (a file).

Which one do I use?

  • Shell → quick experiments, checking "what does this do?", trying a single line.
  • Editor → real programs you want to save, re-run, and build on.

You'll bounce between both all the time: start in the shell to play, move to the editor when you're building something to keep.

Going deeper (optional): the official IDLE documentation is the complete reference. Fair warning — it's thorough and a bit dense (it's a reference, not a tutorial), so don't feel you need to read it all. It's there for when you want the full details on a menu or shortcut.

  1. Affiliate link — if you buy through it, Dakota Learns may earn a small commission at no extra cost to you, which helps keep this work free. Here's why; you're always welcome to find it elsewhere. ↩

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