Python 3 Deep Dive Part 4 Oop 📌

[ Metaclass: type ] │ (Constructs the class object) ▼ [ Class Namespace: CourseSection ] ───► Contains Descriptors, Functions, Class Variables │ (Instantiates via __new__ & __init__) ▼ [ Instance Namespace: course_obj ] ───► Contains Bound Methods, Instance Variables

Classes themselves are objects created by type . This uniformity enables powerful metaclass programming.

Every object in Python (unless optimized) stores its attributes in a dictionary called __dict__ . Understanding this helps debug how Python finds attributes. Class and Instance Methods

: The __init__ method of immutable objects (like tuple , str , int ) is called after the object is immutable; you must override __new__ . python 3 deep dive part 4 oop

: High-level concepts including the __new__ method, class creation mechanics, and the implementation of custom metaclasses . Prerequisites

ABCs also support , allowing you to register a class as a subclass of an ABC without inheriting from it. This is useful when working with third-party classes that you cannot modify directly.

def drive(self): return f"self.engine.start(), self.wheels.rotate()" [ Metaclass: type ] │ (Constructs the class

: Detailed look at read-only and computed properties, including how to use for lazy loading and caching. Methods and Binding

When a subclass inherits from two classes that share a common ancestor, Python uses the MRO to determine which method executes.

class Counter: count = 0 @classmethod def increment(cls): cls.count += 1 Understanding this helps debug how Python finds attributes

class Shape(ABC): @abstractmethod def area(self): """Calculate the area. Must implement.""" pass

End of Report – Python 3 Deep Dive Part 4: OOP

: Disables the __get__ descriptor modification entirely, ensuring the function remains a plain, unaltered function object. 5. Metaclasses: The Creators of Classes

Method overriding is when a subclass provides a different implementation of a method that is already defined in its superclass.