tutorial.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Tutorial — Learn Python v2</title>
  <meta name="description" content="Learn Python v2 step by step: 10 short lessons with runnable examples. Print, variables, f-strings, lists, maps, loops, functions, closures and more.">
  <link rel="icon" type="image/svg+xml" href="favicon-v2.svg">
  <link rel="stylesheet" href="style.css">
</head>
<body>
  <a class="skip-link" href="#main-content">Skip to content</a>

  <!-- ============ top utility bar ============ -->
  <div class="topbar">
    <nav class="topbar-inner" aria-label="Site">
      <a href="index.html">Python</a>
      <a href="index.html#community">PSF</a>
      <a class="active" href="docs.html">Docs</a>
      <a href="download.html">PyPI</a>
      <a href="games.html">Games</a>
      <a href="index.html#community">Community</a>
    <a href="playground.html">Playground</a></nav>
  </div>

  <!-- ============ masthead ============ -->
  <header class="masthead">
    <div class="masthead-inner">
      <a class="brand" href="index.html">
        <img src="logo-v2.svg" alt="Python v2 logo — two snakes, red and blue" width="64" height="64">
        <span class="brand-word">python<sup>™</sup><em>v2</em></span>
      </a>
      <div class="masthead-tools">
        <a class="btn-youtube" href="https://www.youtube.com/@CubeCometYT" target="_blank" rel="noopener">▶ Subscribe</a>
        <form class="searchbox" id="search-form" role="search">
          <span class="search-mag" aria-hidden="true">⌕</span>
          <label class="sr-only" for="search-input">Search</label>
          <input type="search" id="search-input" placeholder="Search">
          <button type="submit" class="btn-go">GO</button>
        </form>
        <button class="btn-social" id="social-btn" type="button">Socialize</button>
      </div>
    </div>
  </header>

  <!-- ============ main nav ============ -->
  <nav class="mainnav" aria-label="Main">
    <div class="mainnav-inner">
      <a href="index.html#about">About</a>
      <a href="download.html">Downloads</a>
      <a href="docs.html">Documentation</a>
      <a href="guide.html">50 Guides</a>
      <a href="games.html">Games</a>
      <a href="index.html#community">Community</a>
    <a href="playground.html">Playground</a></div>
  </nav>

  <!-- ============ page head ============ -->
  <section class="page-head">
    <div class="page-head-inner">
      <h1>The Python v2 Tutorial</h1>
      <p>Ten short lessons from zero to writing real programs. Every example on
        this page is <strong>runnable</strong> — press <strong>Load &amp; run</strong>
        and watch the interpreter do its thing, right here in your browser.
        Already know Python? You'll finish this in ten minutes.</p>
    </div>
  </section>

  <aside class="youtube-callout">
    <div class="youtube-play" aria-hidden="true">▶</div>
    <div><span class="eyebrow">VIDEO INSTALL TUTORIAL AT 1K</span>
      <h2>Subscribe to Cube Comet</h2>
      <p>When @CubeCometYT reaches 1,000 subscribers, the complete Python v2 +
        PyHope installation video will be released.</p></div>
    <a class="btn-youtube btn-youtube-big" href="https://www.youtube.com/@CubeCometYT" target="_blank" rel="noopener">Subscribe on YouTube</a>
  </aside>

  <!-- ============ sandbox ============ -->
  <section class="doc-section" id="sandbox">
    <div class="doc-section-inner">
      <h2><span class="badge">▶</span> The Sandbox</h2>
      <p>This is the real Python v2 interpreter running in your browser. Edit
        anything and press Run (or <kbd>Ctrl</kbd>+<kbd>Enter</kbd>). Every
        “Load &amp; run” button below drops its example here.</p>
      <div class="benchmark-note"><strong>Need a full workspace?</strong> The new
        <a href="playground.html">Playground</a> adds line numbers, Python v2 and
        Classic compatibility modes, command history, a separate error terminal,
        downloadable source, and a live website workshop. Start here for each
        lesson, then move there when you want to experiment.</div>
      <div class="try-grid">
        <div class="try-editor">
          <label class="sr-only" for="sb-code">Python v2 source</label>
          <textarea id="sb-code" spellcheck="false">print("Hello, World!")</textarea>
          <button class="btn btn-blue btn-inline" id="sb-run" type="button">▶ Run</button>
        </div>
        <div class="try-out" id="sb-output" aria-live="polite"></div>
      </div>
    </div>
  </section>

  <!-- ============ lessons ============ -->
  <main id="main-content" class="doc-section">
    <div class="doc-section-inner">

      <!-- LESSON 1 -->
      <h2 id="lesson-1"><span class="badge">01</span> Hello, World!</h2>
      <p>Python v2 programs are plain text files ending in <code>.pyv2</code>.
        The <code>print</code> function shows things on screen, and
        <code>#</code> starts a comment.</p>
      <pre class="terminal"><code># hello.pyv2
print("Hello, World!")
print("2 + 2 =", 2 + 2)</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='print("Hello, World!")
print("2 + 2 =", 2 + 2)'>Load &amp; run ▶</button></p>
      <p>On your computer, run it with
        <code>python3 -m pyv2 hello.pyv2</code> —
        <a href="download.html">get the language here</a>.</p>

      <!-- LESSON 2 -->
      <h2 id="lesson-2"><span class="badge">02</span> Variables &amp; Values</h2>
      <p>Just write <code>name = value</code> — no declarations, no semicolons.
        Python v2 has numbers, strings, booleans, and <code>nil</code>
        (the “nothing” value). Ask <code>type(x)</code> whenever you're curious.</p>
      <pre class="terminal"><code>name = "Ada"
age = 36
pi = 3.14
coding = true
gift = nil

print(name, age, pi, coding, gift)
print(type(name), type(age), type(coding), type(gift))</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='name = "Ada"
age = 36
pi = 3.14
coding = true
gift = nil

print(name, age, pi, coding, gift)
print(type(name), type(age), type(coding), type(gift))'>Load &amp; run ▶</button></p>

      <!-- LESSON 3 -->
      <h2 id="lesson-3"><span class="badge">03</span> Math</h2>
      <p>All the usual operators, plus three you'll love:
        <code>//</code> is floor division, <code>%</code> is remainder, and
        <code>**</code> is power. Division always gives you a real number —
        <code>10 / 4</code> is <code>2.5</code>, not <code>2</code>.</p>
      <pre class="terminal"><code>print(10 / 4, 10 // 4, 7 % 3, 2 ** 10)
print(-7 // 2, -7 % 3)        # floored, Python-style
print("n=" + 42)              # strings + numbers just work</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='print(10 / 4, 10 // 4, 7 % 3, 2 ** 10)
print(-7 // 2, -7 % 3)
print("n=" + 42)'>Load &amp; run ▶</button></p>

      <!-- LESSON 4 -->
      <h2 id="lesson-4"><span class="badge">04</span> Strings &amp; F-Strings</h2>
      <p>The star of the show: <strong>f-strings</strong>. Put
        <code>f</code> before a string and <code>{anything}</code> inside it —
        expressions included. Strings come with friendly methods:
        <code>upper</code>, <code>split</code>, <code>contains</code>, …</p>
      <pre class="terminal"><code>name = "python v2"
print(f"Hello, {name}!")
print(f"next year: {2026 + 1}, fast: {2 ** 8}")
print(f"{{braces}} survive when doubled")

print(name.upper(), name.title())
print("a,b,c".split(",").join(" - "))
print("hello".contains("ell"), "hello".slice(1, 3))</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='name = "python v2"
print(f"Hello, {name}!")
print(f"next year: {2026 + 1}, fast: {2 ** 8}")
print(f"{{braces}} survive when doubled")

print(name.upper(), name.title())
print("a,b,c".split(",").join(" - "))
print("hello".contains("ell"), "hello".slice(1, 3))'>Load &amp; run ▶</button></p>

      <!-- LESSON 5 -->
      <h2 id="lesson-5"><span class="badge">05</span> Lists</h2>
      <p>Lists keep things in order. Index with <code>xs[0]</code>
        (or <code>xs[-1]</code> for the last), and use the methods that spark
        joy: <code>push</code>, <code>sort</code>, <code>join</code>, …</p>
      <pre class="terminal"><code>xs = [3, 1, 2]
xs.push(4)
print(xs, xs.sort(), xs[-1])

names = ["Ada", "Grace"]
names.insert(0, "Edsger")
print(names, names.join(", "), len(names))
print([1, 2] + [3], [1, 2] * 2)
print("sum:", sum(xs), "numbered:", enumerate(names, 1))
print("paired:", zip(names, [36, 85, 92]))</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='xs = [3, 1, 2]
xs.push(4)
print(xs, xs.sort(), xs[-1])

names = ["Ada", "Grace"]
names.insert(0, "Edsger")
print(names, names.join(", "), len(names))
print([1, 2] + [3], [1, 2] * 2)
print("sum:", sum(xs), "numbered:", enumerate(names, 1))
print("paired:", zip(names, [36, 85, 92]))'>Load &amp; run ▶</button></p>

      <!-- LESSON 6 -->
      <h2 id="lesson-6"><span class="badge">06</span> Maps</h2>
      <p>Maps hold labeled values. Bare keys become strings, dot access reads
        them, and <code>get(key, default)</code> never explodes when the key is
        missing.</p>
      <pre class="terminal"><code>hero = {
    name: "Ada",
    scores: [10, 20, 30],
}
hero.city = "London"

print(hero.name, hero["city"])
print(hero.scores)
hero.scores.push(40)
print(hero.scores)
print(hero.get("pet", "none"), hero.has("name"))</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='hero = {
    name: "Ada",
    scores: [10, 20, 30],
}
hero.city = "London"

print(hero.name, hero["city"])
print(hero.scores)
hero.scores.push(40)
print(hero.scores)
print(hero.get("pet", "none"), hero.has("name"))'>Load &amp; run ▶</button></p>

      <!-- LESSON 7 -->
      <h2 id="lesson-7"><span class="badge">07</span> Decisions</h2>
      <p><code>if</code> / <code>elif</code> / <code>else</code> blocks end
        with <code>end</code> — no indentation errors, ever. And the ternary
        reads like a question: <code>ok ? "yes" : "no"</code>.</p>
      <pre class="terminal"><code>score = 87

if score >= 90:
    grade = "A"
elif score >= 80:
    grade = "B"
else:
    grade = "C"
end

print(f"score {score} → grade {grade}")
print(score > 60 ? "passed" : "failed")</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='score = 87

if score >= 90:
    grade = "A"
elif score >= 80:
    grade = "B"
else:
    grade = "C"
end

print(f"score {score} -> grade {grade}")
print(score > 60 ? "passed" : "failed")'>Load &amp; run ▶</button></p>

      <!-- LESSON 8 -->
      <h2 id="lesson-8"><span class="badge">08</span> Loops</h2>
      <p><code>for x in …</code> walks lists, strings, maps and
        <code>range()</code>. <code>while</code> repeats until you say stop —
        with <code>break</code> and <code>continue</code> when you need them.</p>
      <pre class="terminal"><code>for i in range(1, 6):
    print(f"i is {i}")
end

total = 0
for n in [1, 2, 3, 4, 5, 6]:
    if n % 2 == 0:
        continue        # skip evens
    end
    total += n
end
print("sum of odds:", total)

for ch in "abc":
    print(ch)
end</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='for i in range(1, 6):
    print(f"i is {i}")
end

total = 0
for n in [1, 2, 3, 4, 5, 6]:
    if n % 2 == 0:
        continue
    end
    total += n
end
print("sum of odds:", total)

for ch in "abc":
    print(ch)
end'>Load &amp; run ▶</button></p>

      <!-- LESSON 9 -->
      <h2 id="lesson-9"><span class="badge">09</span> Functions &amp; Closures</h2>
      <p>Define functions with <code>fn</code>, give values back with
        <code>return</code>. Functions are just values — pass them around. And
        inner functions remember the world they were born in (real closures,
        no <code>nonlocal</code> nonsense).</p>
      <pre class="terminal"><code>fn greet(name):
    return f"Hello, {name}!"
end

fn make_counter():
    n = 0
    fn bump():
        n += 1
        return n
    end
    return bump
end

print(greet("World"))

counter = make_counter()
counter()
counter()
print("count:", counter())

sq = fn(x): return x * x end
print("7² =", sq(7))</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='fn greet(name):
    return f"Hello, {name}!"
end

fn make_counter():
    n = 0
    fn bump():
        n += 1
        return n
    end
    return bump
end

print(greet("World"))

counter = make_counter()
counter()
counter()
print("count:", counter())

sq = fn(x): return x * x end
print("7^2 =", sq(7))'>Load &amp; run ▶</button></p>

      <!-- LESSON 10 -->
      <h2 id="lesson-10"><span class="badge">10</span> Errors, Recovery &amp; Cleanup</h2>
      <p>Failures carry a kind, message, source line, and call trace. Protect work
        with <code>try</code>, recover in <code>catch error</code>, and put cleanup
        in <code>finally</code> so it runs even during a return or loop jump.
        Use <code>raise</code> for your own application errors.</p>
      <pre class="terminal"><code>fn divide(a, b):
    assert(b != 0, "b must not be zero")
    return a / b
end

try:
    print(divide(10, 0))
catch error:
    print(error.kind + ":", error.message)
    print("line:", error.line)
finally:
    print("calculation finished")
end

try: raise {kind: "ConfigError", message: "port required"}
catch error: print(error.kind, error.message)
end</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='fn divide(a, b):
    assert(b != 0, "b must not be zero")
    return a / b
end

try:
    print(divide(10, 0))
catch error:
    print(error.kind + ":", error.message)
    print("line:", error.line)
finally:
    print("calculation finished")
end

try: raise {kind: "ConfigError", message: "port required"}
catch error: print(error.kind, error.message)
end'>Load &amp; run ▶</button></p>

      <!-- FINAL -->
      <h2 id="next"><span class="badge">★</span> What's Next</h2>
      <p>You now know the whole language. Seriously — that was it. Go build
        something:</p>
      <ul class="checklist">
        <li><strong><a href="download.html">Install it</a></strong> on your
          machine and run <code>examples/fizzbuzz.pyv2</code>.</li>
        <li><strong><a href="docs.html">Read the docs</a></strong> — full
          builtin &amp; method reference, plus editor setup.</li>
        <li><strong><a href="docs.html#windows-apps">Build a Windows app</a></strong>
          with <code>pyv2 new windows-app "My App"</code>, safe JSON data, and a
          reproducible one-file EXE workflow.</li>
        <li><strong><a href="index.html#game">Play the CPU raycaster</a></strong>
          and then read <code>examples/terminal_raycast.pyv2</code> —
          the whole engine in one file.</li>
        <li><strong><a href="https://github.com/gefrus112/pythonv2">Join the fun on GitHub</a></strong>
          — stars, issues and pull requests all accepted.</li>
      </ul>
      <p>Graduation project: write FizzBuzz from memory, the Python v2 way —</p>
      <pre class="terminal"><code>for i in range(1, 16):
    if i % 15 == 0:
        print("FizzBuzz")
    elif i % 3 == 0:
        print("Fizz")
    elif i % 5 == 0:
        print("Buzz")
    else:
        print(i)
    end
end</code></pre>
      <p><button class="btn btn-blue btn-inline load-run" data-code='for i in range(1, 16):
    if i % 15 == 0:
        print("FizzBuzz")
    elif i % 3 == 0:
        print("Fizz")
    elif i % 5 == 0:
        print("Buzz")
    else:
        print(i)
    end
end'>Load &amp; run ▶</button></p>

    </div>
  </main>

  <!-- ============ footer ============ -->
  <footer class="footer">
    <div class="footer-inner">
      <div class="footer-col">
        <h4>Navigation</h4>
        <a href="index.html#about">About</a>
        <a href="download.html">Downloads</a>
        <a href="docs.html">Documentation</a>
        <a href="index.html#community">Community</a>
        <a href="games.html">Games</a>
      </div>
      <div class="footer-col">
        <h4>Downloads</h4>
        <a href="download.html#get">Get the language</a>
        <a href="https://github.com/gefrus112/pythonv2/archive/refs/heads/main.zip">Download ZIP</a>
        <a href="https://github.com/gefrus112/pythonv2">GitHub repo</a>
        <a href="download.html#install">Install steps</a>
      </div>
      <div class="footer-col">
        <h4>Documentation</h4>
        <a href="tutorial.html">Tutorial</a>
        <a href="guide.html">50-topic guide</a>
        <a href="docs.html#pyhope">PyHope guide</a>
        <a href="docs.html#install">Installation</a>
        <a href="docs.html#vscode">VS Code setup</a>
        <a href="docs.html#any-editor">Any editor</a>
      </div>
      <div class="footer-col">
        <h4>Community</h4>
        <a href="https://github.com/gefrus112/pythonv2">GitHub</a>
        <a href="https://github.com/gefrus112/pythonv2/issues">Issues</a>
        <a href="index.html#news">News</a>
        <a href="index.html#events">Events</a>
      </div>
      <div class="footer-col">
        <h4>Success Stories</h4>
        <a href="index.html#game">CPU raycaster</a>
        <a href="index.html#start">Terminal raycast</a>
        <a href="index.html#about">This very website</a>
      </div>
    </div>
    <div class="footer-legal">
      <p>
        <img src="favicon-v2.svg" alt="" width="22" height="22">
        © <span id="year">2026</span> Python v2 Software Foundation™ — a fan-made remake,
        not affiliated with the Python Software Foundation. Powered by pure CPU rendering
        and stubborn optimism.
      </p>
      <p class="footer-meta">
        <a href="index.html#about">Privacy</a> · <a href="index.html#about">Terms</a> ·
        <a href="https://github.com/gefrus112/pythonv2">GitHub</a>
      </p>
    </div>
  </footer>

  <script src="pyv2.js"></script>
  <script src="site.js"></script>
  <script>
    // tutorial: shared sandbox + load-and-run buttons
    (function () {
      "use strict";
      const codeEl = document.getElementById("sb-code");
      const outEl = document.getElementById("sb-output");

      function runSandbox() {
        const r = Pyv2.runCapture(codeEl.value);
        outEl.textContent = r.error ? (r.output ? r.output + "\n" : "") + r.error : r.output;
        outEl.classList.toggle("error", !!r.error);
      }

      document.getElementById("sb-run").addEventListener("click", runSandbox);
      codeEl.addEventListener("keydown", (e) => {
        if ((e.ctrlKey || e.metaKey) && e.key === "Enter") {
          e.preventDefault();
          runSandbox();
        }
      });

      document.querySelectorAll(".load-run").forEach((btn) => {
        btn.addEventListener("click", () => {
          codeEl.value = btn.getAttribute("data-code") || "";
          runSandbox();
          document.getElementById("sandbox").scrollIntoView({ behavior: "smooth", block: "start" });
        });
      });

      document.getElementById("search-form").addEventListener("submit", (e) => {
        e.preventDefault();
        const v = document.getElementById("search-input").value.trim();
        window.location.href = "docs.html" + (v ? "?q=" + encodeURIComponent(v) : "") + "#language";
      });
      document.getElementById("social-btn").addEventListener("click", () => {
        window.location.href = "index.html#community";
      });
      const y = document.getElementById("year");
      if (y) y.textContent = String(new Date().getFullYear());
    })();
  </script>
</body>
</html>