Inheritance & Dunder Methods

Definition

Inheritance lets a class reuse and extend another; dunder methods like __str__ and __len__ customize built-in behavior.

Core to writing clean object-oriented Python.

Diagram

Flowchart

Example: Override + __str__

class Animal:
    def speak(self): return '...'
class Dog(Animal):
    def speak(self): return 'Woof'
    def __str__(self): return 'Dog'
d = Dog()
print(d, d.speak())

Output: Dog Woof

Key points

• super() calls the parent
• __eq__ and __hash__ go together

Interview questions

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