🐍 LearnPy — Learn Python by Playing

A self-contained, browser-based game that teaches you real Python — no installs, no accounts, no internet needed. Just open index.html.

🎮 What is it?

▶ Play online: davidcanarnt.github.io/learnpy (or download and double-click index.html — no install, no internet needed)

You are shipwrecked on Snake Island with Pip the python. Fix the Great Bug's chaos across 10 worlds and 64 levels, earning XP, stars, streaks and achievements along the way.

Every level runs your code on a real Python interpreter built into the page (a custom, sandboxed subset written in JavaScript — see js/pyengine.js). If it runs in LearnPy, the same code runs in Python 3.

The worlds

#	World	You learn
1	🌴 Hello, Snake Island	print(), strings, comments, sep=
2	📦 Variable Valley	variables, arithmetic, // vs /, input(), round()
3	🐚 String Shore	f-strings, methods, indexing, slicing, replace()
4	🌊 List Lagoon	lists, indexes, append, sort, sum/min/max
5	🔀 Decision Delta	if/elif/else, and/or, in, == vs =
6	🌀 Loop Lagoon	for, range(), while, break/continue, patterns
7	⚙️ Function Falls	def, parameters, defaults, return, reuse in loops
8	🗝️ Dict Depths	dictionaries, .get(), looping .items(), vote counter
9	🐢 Turtle Peak	draw with code: squares, spirals, stars, free art
10	👑 The Great Bug	boss fight: debug a broken program, final trial

Level types keep it fresh: write code (with a real editor), answer quizzes, re-assemble scrambled programs, and fill in the blanks.

✨ Why it's (hopefully) addictive

• 💗 Hearts — failed runs cost one; wins restore them
• 🔥 Streaks — consecutive successful runs multiply your XP
• ⭐ 3-star levels — first try, no hints
• 🏆 15 achievements, 8 ranks (Byte Rookie → Serpent Master)
• 🎯 Challenge of the Day — a fresh bonus quiz every day
• 💾 Progress auto-saves in your browser (localStorage)
• 🎉 Confetti, sound effects (WebAudio), an animated turtle, and a mascot with opinions
• 🧪 Sandbox with turtle graphics + examples — zero grades, pure experiments

🚀 How to run

Play online: davidcanarnt.github.io/learnpy

Or locally: double-click index.html (Chrome, Edge or Firefox). That's it. Everything — interpreter, levels, styles — is local. No build step, no server, no network.

Tip: Ctrl+Enter runs your code. Tab indents, Shift+Tab outdents, Enter auto-indents.

🧠 The Python subset

Supported: variables & assignment (incl. tuple swap), ints/floats/strings/booleans, f-strings with format specs, lists, tuples, dicts, if/elif/else, while, for … in, def with defaults, return, break/continue, indexing & slicing, comparison/boolean operators, the main builtins (print, len, range, input, sorted, enumerate, zip, …), string/list/dict methods, and random / math / turtle modules.

Deliberately Python-faithful details: / always returns a float (4/2 → 2.0), // floors toward negative infinity, % follows the divisor's sign, round() is banker's rounding, dicts preserve insertion order, and range() excludes its end.

Not supported (with friendly errors pointing the way): classes, list comprehensions (use a loop + .append()), try/except, lambda, sets.

📁 Project layout

learnpy/
├── index.html          ← open this
├── css/style.css       ← the looks
├── js/pyengine.js      ← custom Python interpreter (tokenizer → parser → evaluator)
├── js/turtle.js        ← animated canvas turtle (records ops so levels can check drawings)
├── js/levels.js        ← curriculum data: worlds, levels, quizzes, achievements
├── js/game.js          ← game logic: screens, XP, hearts, streaks, sound, confetti
└── test/               ← 494 automated tests (engine + every level's solution)

🧪 Tests

node test/run_tests.js    # 161 engine tests
node test/test_levels.js  # 333 curriculum tests (every solution runs & matches)

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Made with ❤️, ⚡ and an unreasonable number of 🐍 puns.