What is the use of the "property" decorator in Python?

Question

Jayant Kumar · Accepted Answer

Table of Contents
Introduction
In Python, the property decorator is used to define methods in a class that can be accessed like attributes. This decorator allows you to create getter, setter, and deleter methods for managing access to an object's attributes while still presenting them as simple attributes. This approach provides a way to encapsulate and control access to data, making your class interface more intuitive and maintainable.
Understanding the property Decorator
The property decorator is used to define a method as a property, which allows you to access it like an attribute while still being able to add logic for getting, setting, or deleting the value. This encapsulation can help enforce data validation, trigger actions on attribute access, or hide the internal implementation details from the class users.
Key Components

Getter Method: Used to retrieve the value of the attribute.
Setter Method: Used to set the value of the attribute with validation or modification.
Deleter Method: Used to delete the attribute.

Using the property Decorator
The property decorator simplifies the creation of managed attributes in a class. It uses the following syntax:
class MyClass:
    def __init__(self, value):
        self._value = value

@property
    def value(self):
        return self._value

@value.setter
    def value(self, new_value):
        if new_value &#x3C; 0:
            raise ValueError("Value must be non-negative")
        self._value = new_value

@value.deleter
    def value(self):
        del self._value

In this example, the value property provides controlled access to the _value attribute. The getter method retrieves the value, the setter method ensures it is non-negative, and the deleter method removes the attribute.
Practical Examples
Example 1: Calculating Properties
You can use the property decorator to define a property that calculates a value dynamically based on other attributes.
class Rectangle:
    def __init__(self, width, height):
        self._width = width
        self._height = height

@property
    def area(self):
        return self._width * self._height

@property
    def perimeter(self):
        return 2 * (self._width + self._height)

Here, area and perimeter are properties that calculate the area and perimeter of a rectangle based on its width and height.
Example 2: Validating Attributes
You can enforce validation rules when setting an attribute using the property decorator.
class Person:
    def __init__(self, age):
        self._age = age

@property
    def age(self):
        return self._age

@age.setter
    def age(self, value):
        if value &#x3C; 0:
            raise ValueError("Age cannot be negative")
        self._age = value

@age.deleter
    def age(self):
        del self._age

In this example, the age property ensures that the age cannot be set to a negative value.
Conclusion
The property decorator in Python is a powerful tool for managing access to class attributes. It allows you to define methods for getting, setting, and deleting attributes while exposing them as simple properties. This approach helps in encapsulating logic, enforcing validation, and maintaining a clean and intuitive interface for your classes.

What is the use of the "property" decorator in Python?

Table of Contents

Introduction

Understanding the `property` Decorator

Key Components

Using the `property` Decorator

Practical Examples

Example 1: Calculating Properties

Example 2: Validating Attributes

Conclusion

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