>>>PyForge

18 lessons · 6 tracks · live interpreter

Python, from first print to the internals.

A serious path through the language: names and objects, control, data, functions, classes, types, concurrency, and the CPython data model. Every lesson has runnable examples, a quiz, and an exercise.

Start the pathOpen playground
The idea that unlocks the rest
def names_are_labels():
    a = [1, 2, 3]
    b = a          # same object
    c = list(a)    # a copy
    b.append(4)
    return a, c

print(names_are_labels())

Assignment never copies. Run it.

Deep, not skimmed

Each concept is taught with the rule, the example, and the gotcha. No toy chapter that stops at print().

A real interpreter

Examples and exercises run in the browser on CPython-via-Pyodide. Infinite loops time out automatically.

A tutor on the lesson

Signed-in learners can ask a focused question about the current page. Guests still get the full path.

Curriculum

Six tracks, in order

  1. 01

    Foundations

    How Python represents names, objects, and text.

    Start here · 0/3 complete

  2. 02

    Control flow

    Branching, iteration, and exceptions as design tools.

    Beginner · 0/3 complete

  3. 03

    Data structures

    Sequences, mappings, sets, and the idioms that use them.

    Beginner · 0/3 complete

  4. 04

    Functions

    Scope, closures, decorators, and lazy generators.

    Intermediate · 0/3 complete

  5. 05

    Objects

    Classes, protocols, modules, and context managers.

    Intermediate · 0/3 complete

  6. 06

    Advanced

    Types, concurrency, and the CPython object model.

    Advanced · 0/3 complete