Python Classes Cheat Sheet, OOP, Dataclasses, Iterators and Generators, Visual Coding Study Guide

A Python classes cheat sheet that shows how objects really work: where Python finds an attribute, what len, for and print call, and how a generator runs.
THIS IS A DIGITAL DOWNLOAD. NO PHYSICAL ITEM WILL BE SHIPPED.
You will receive printable PDF files in one ZIP file. No printed or laminated sheets are included. The photos show how they look once printed.

SEE WHAT PYTHON DOES WITH YOUR CLASSES
A visual study guide to Python classes and iteration on two sheets, printed on both sides. Instead of a list of rules, it draws what Python does: which object holds each attribute, which special method a built-in calls, which class a lookup stops at, and which line a generator runs next. One small running example (a delivery van with a capacity and its parcels) grows through all four pages, so you learn it once and follow it everywhere. Every code example shows its real result.

SHEET 1, FRONT - CLASSES & INSTANCES
- one class, two objects, drawn: an instance's own attributes and the attributes it finds on its class
- shadowing: assigning to an instance adds a row to that instance only
- methods and self: south.load(tea) runs Van.load(south, tea)
- what Van("North", 3) does, in three frames: a new object, __init__ fills it, the call returns it

SHEET 1, BACK - SPECIAL METHODS & DATACLASSES
- @property: a value computed when you read it, without brackets
- what len, for, in and print call: four call paths traced to __len__, __iter__ and __repr__
- == without __eq__, and membership without __contains__
- what @dataclass writes for you (__init__, __repr__, __eq__), field by field

SHEET 2, FRONT - INHERITANCE & COMPOSITION
- a subclass is searched before its base: the lookup chain, drawn
- super().__init__ and super() to extend a method; __mro__ and isinstance with real results
- inherit or compose? a starting-point chart
- functions as arguments: lambda with key=, *args and **kwargs, and * to unpack

SHEET 2, BACK - ITERATORS & GENERATORS
- what "for p in north:" does: iter() once, then next() until StopIteration, written out as a while loop
- iterables vs iterators, side by side: which ones can you loop over twice?
- a generator, traced one next() at a time: where it pauses, what it remembers
- generator expressions

Common surprises are shown right next to their topic (forgetting self, a list as a class attribute shared by every object, a list default in a dataclass, a used-up generator that gives nothing, and more).

TEST YOURSELF VERSION
The same pages with the answers left blank: write the missing method, predict the results, repair a subclass and trace two generators. Fill them in from memory, then check yourself against the cheat sheet.

WHAT YOU GET: 8 PDF FILES (in one ZIP)
- Cheat Sheet and Test Yourself
- 2 colour styles: Color, and Gray (uses less coloured ink)
- 2 paper sizes: A4 and US Letter
- each file is two sheets: 4 pages, print double-sided ("flip on long edge")
- a short READ ME with printing tips

WHO IT IS FOR
Beginners who can write functions and use lists and dictionaries, and now meet classes; students in a first programming course; self-taught learners and career changers; anyone starting a data science course who wants to understand the objects they use. Assumes basic Python.

HOW IT IS MADE
Typeset in LaTeX; every diagram is drawn by code from the real objects, no AI image generator was used. The content and the code were prepared with help from an AI assistant. Every code example on the sheet was run by a script in Python 3.12 and its result checked, and the content went through several independent reviews.

HOW IT WORKS
1. Purchase the listing.
2. Download the ZIP file instantly from Purchases & Reviews in your Etsy account (or from the link in your confirmation email) and unzip it.
3. Print at home or at a print shop at 100% / "actual size", double-sided, or open the PDF on a tablet.

PLEASE NOTE
- This is a digital product. Nothing will be shipped.
- This is a focused study guide to classes and iteration, not a complete Python reference.
- Due to the nature of digital downloads, refunds are not accepted. Send us a message if you have any problem with your files and we'll gladly help.
- Colours may vary slightly between screens and printers.
- For personal use only. You may print as many copies as you need for yourself. Teachers: please message us about classroom use. Reselling or sharing the files is not allowed. (c) MIRAICO Academy, all rights reserved.
- Independent educational resource. Not affiliated with or endorsed by the projects mentioned.

Also in the shop: Python Essentials and Python Data Structures (the steps before), or all three together in the Python Beginner Cheat Sheet Bundle.

At MiraicoAcademy, we show how things work, not just what to type.