naturally, the credit for the contents here go to refactoring.guru
Oop
2026-04-29
Table of Contents
there are three main categories of Design Patterns as decreed by the ‘Gang of Four’1 (the authors of a seminal work Design Patterns | Elements of Reusable Object-Oriented Software). the content here is largely based on Dive into Design Patterns by Alexander Shvets2.
Table of Contents
overview
the Unified Modelling Language (UML) is a standardised visual language for specifying, constructing, and documenting software systems.
Data Types
| category | types |
|---|---|
| text | str |
| numeric | int, float, complex |
| sequence | list, tuple, range |
| mapping | dict |
| set | set, frozenset |
| boolean | bool |
| binary | bytes, bytearray, memoryview |
| none | NoneType |
Keywords
Python reserves 35 hard keywords (plus the soft keywords match and case for structural pattern matching since 3.10). Reserved keywords cannot be used as identifiers; soft keywords are only special in the relevant context.