Start Here — how to run any project

New here? Read this once. It shows you the two ways to run a project — in your browser with nothing to install, or on your own computer — and how to tell each step worked. Every project links back here, so you only learn this once.

You do not need a GitHub account, and you do not need git. You get the code straight from the course website.

In a hurry?

If the project page has a ▶ Run button, click it and skip to Run it in your browser. If you’d rather run it on your own machine, go to Run it on your computer.

Reading the labels in the sidebar

Each project in the left menu carries a small chip and a number — the level and the difficulty (1–10): AbsBeg (absolute beginner, 1–2), Beg (beginner, 3–4), Int (intermediate, 5–6), Adv (advanced, 7–8). A trailing ▶ means the project runs in your browser — no install. Never coded before? Start with an AbsBeg project that has a ▶, so your first click just works.

What a project looks like

Every project is a small set of files that work together:

• a README (the tutorial you’re reading on the site),
• a data/ script that makes the practice data for you (it’s generated on your machine — nothing to download),
• a Part A script — the guided build you read and run step by step,
• a Part B folder — your turn: a similar problem you solve yourself, with a test you can run to check your answer,
• a requirements.txt listing the exact tools the project uses.

Each project has two parts:

• Part A — Guided Build. Everyone can do this. You run working code, one step at a time, and each step tells you what you should see. This is the core of the course.
• Part B — Your Turn (intermediate / optional). A fresh problem you solve by writing your own code. It assumes you can already write a little Python. If you’re brand new, do Part A first and come back to Part B when you’re ready — skipping it is completely fine.

Option A — Run it in your browser (nothing to install)

Many projects have a ▶ Run button on their page. When you click it, the code runs inside your web browser — there’s nothing to install, and nothing can go wrong with your computer’s setup.

1. Open the project page on the course site.
2. Find the ▶ Run button (usually next to Part A) and click it.
3. Wait a few seconds the first time — the browser is loading Python. This is normal and only slow once.
4. Output appears right below the button. Read it against the “you should see…” checkpoints in the tutorial.

This is the easiest way to start, and it’s the recommended path for Part A. Some projects need tools that don’t run in the browser yet; those will say so and point you to Option B.

Option B — Run it on your computer

This is the full setup. It works for every project (including Part B, where you write and test your own code). You need Python 3.11 or newer. Everything is free — no accounts, no GPU, no paid tools.

Honest heads-up: the first time, this takes about 15 minutes and it’s the fussiest part of the whole course — but you only do it once per computer, and after that every project is just a couple of commands. If it feels like too much right now, pick a project with a ▶ Run button instead and come back to this later.

1. Get Python (once per computer)

First check whether you already have it. Open a terminal — that’s Command Prompt on Windows, or Terminal on macOS/Linux — and type:

python --version

• If it prints Python 3.11 or higher, you’re set.
• If it says “not found,” or on Windows it opens the Microsoft Store, install from python.org/downloads.
  • Windows: in the installer, tick “Add python.exe to PATH” (easy to miss — nothing works without it). If python still isn’t found, type py instead of python everywhere below.
  • macOS/Linux: if python isn’t found, try python3 (and pip3) instead.

A free editor helps but isn’t required — VS Code is a good first choice.

2. Get the project’s code from the course site

On the project’s page, click Download the code. You’ll get a ZIP file (a compressed folder).

1. Find the ZIP in your Downloads folder.
2. Unzip it (Windows: right-click → Extract All; macOS: double-click it).
3. You now have a folder with the project’s name, containing README.md, requirements.txt, and the data/, part_a/, and part_b/ folders.

(No GitHub, no git — just a download, like any other file.)

3. Open a terminal inside the project folder

You must run the commands from inside the project folder (that’s where the scripts look for their data/ folder).

• Windows: open the folder in File Explorer, click the address bar, type cmd, and press Enter — a Command Prompt opens already in that folder.
• macOS: open Terminal, type cd (with a trailing space), then drag the project folder onto the window and press Enter.
• Linux: right-click the folder → “Open Terminal Here,” or cd /path/to/the-project.

Check you’re in the right place: dir (Windows) or ls (macOS/Linux) should list requirements.txt and the data/, part_a/, part_b/ folders.

4. Create a virtual environment and install the tools

A virtual environment (“venv”) is a private box for this project’s tools, so they don’t clash with anything else on your computer. One-time setup, from inside the project folder:

Windows:

python -m venv .venv
.venv\Scripts\activate
python -m pip install -r requirements.txt

macOS/Linux:

python3 -m venv .venv
source .venv/bin/activate
python3 -m pip install -r requirements.txt

Your prompt shows (.venv) once the box is active. Installing is done when you see Successfully installed …. Every time you open a new terminal to work on the project, run the activate line again first.

Confirm it worked:

python -c "import pandas, numpy, pytest; print('setup OK')"

If that prints setup OK, you’re ready.

5. Run the project

Each tutorial gives the exact commands, but the shape is always:

python data/make_data.py        # make the practice data (safe to re-run)
python part_a/<script>.py        # Part A — the guided build
# ... then, for Part B, you write your solution and check it:
python part_b/starter.py
pytest part_b/test_solution.py -q

6. Reading Part A one step at a time (recommended)

Part A is meant to be read and run one STEP at a time, so you can check each checkpoint before moving on. Two easy ways:

• In an editor with cells (smoothest). The Part A script is split into cells marked # %%, one per STEP. In VS Code (with the Python extension), a ▷ Run Cell link appears above each # %% — click it, or press Shift+Enter. Output shows in a side panel and variables stay between cells.
• In the plain Python prompt. Run python from the project folder, then paste each STEP’s block one at a time. The scripts are written to work here too.

Type exit() to leave the Python prompt.

Troubleshooting (the errors beginners actually hit)

• python not found / opens the Store (Windows): use py instead (py -m venv .venv, …), or reinstall Python with “Add to PATH” ticked.
• pip not found: use python -m pip … — it always works when python does.
• FileNotFoundError for a CSV: you’re not inside the project folder, or you skipped python data/make_data.py. Check with dir/ls, then re-run from the project folder.
• Tools “not installed” after reopening the terminal: re-activate the venv (.venv\Scripts\activate on Windows, source .venv/bin/activate elsewhere).
• The browser ▶ Run is slow the first time: that’s Python loading in the browser. It’s only slow once; give it a few seconds.
• pytest says everything is “skipped”: that’s expected until you’ve produced the output the test checks — run your Part B solution (python part_b/starter.py) first, then re-run the test.

Still stuck on setup? You don’t need to fight it — the browser ▶ Run option (where available) skips all of this.