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Intermediate 18 min readModule: Module 7: Object-Oriented Python & Dunder Methods

OOP, Dunder Methods & Properties (@property)

Master classes, __repr__, __eq__, getters/setters with @property, and method overriding.

What You Will Learn in This Lesson

  • Object-Oriented classes, constructors (__init__), and inheritance
  • Special Dunder methods (__str__, __repr__, __len__, __eq__)
  • Encapsulating getters/setters with the @property decorator

Introduction & Core Concept

In Python, everything is an object. Custom classes define encapsulated data and behavior. Special double-underscore ('dunder') methods allow classes to integrate with Python language features.
WHY DOES THIS MATTER IN THE REAL WORLD?

Implementing __repr__ and __eq__ allows objects to be printed and compared naturally with ==.

Custom Class with Dunder Methods

python
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class Developer:
    def __init__(self, name: str, level: int):
        self.name = name
        self.level = level
 
    def __repr__(self) -> str:
        return f"Developer(name='{self.name}', level={self.level})"
 
    def __eq__(self, other) -> bool:
        return isinstance(other, Developer) and self.level == other.level
 
d1 = Developer("Alex", 3)
d2 = Developer("Sarah", 3)
print(d1)
print(f"Equal Experience Level: {d1 == d2}")

Line-by-Line Technical Breakdown

1@property allows method calls to look like standard attribute access without breaking public APIs.

Try It Yourself (Interactive Editor)

Modify the code in real-time and click Run to test live browser output and console logs.

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Industry Best Practices & Professional Standards

  • Always implement __repr__ on domain data model classes.

Lesson Summary & Core Takeaways

  • Dunder methods allow custom classes to integrate seamlessly into Python's object model.