Topic 10. Special methods and operator overloading, data classes and enumerations

Goal: learn to implement arithmetic and container protocols, design immutable values, data classes, and enumerations, and check consistency between equality, hashing, and operations.

Lecture contents

1. The data model and arithmetic operations — The data model and special methods · Object representations for users and developers · Arithmetic operations and NotImplemented
2. Comparison, hashing, and containers — Equality, ordering, and hashing · The container protocol and callable objects
3. Context managers — Context managers
4. Data classes and enumerations — Data classes and generated methods · Enumerations and flags · Structural class patterns · Testing value types and common mistakes

Practice and review

• Practice — 3 worked examples with complete code
• Tasks — 30 variants, each with tasks at three difficulty levels
• Summary — conclusions, self-check questions, and useful links