Python Classes and Objects Archives: 20 Building Blocks for Deep Understanding

Classes and objects are the cornerstones of Object-oriented programming (OOP) in python. Classes act as blueprints for objects, and objects are instances of classes. By understanding these concepts, developers can create code that is flexible, reusable, and easy to maintain. kind

A class is a user-defined type that encapsulates data and methods.

An instance of a class corresponds to an object.
Classes are declared by the
• class
keyword, followed by the class name.
• Classes contain data members (properties) and methods (operations).
• Object

Objects are instances of classes.

Object references properties and methods in the class.
Objects are created using the
• class
keyword.
• Access the properties and methods of an object through the period operator (.).
• Creation of classes

Example:

class Person: def __init__(self, name, age): self.name = name self.age = age

This code creates a class named

Person

which has a constructor

__init__ which sets the name and for the newly created object age attribute. Creation of objects

Example:

person1 = Person("John", 30)

This code creates an object of class

Person

named

person1 and sets its name and age properties respectively. for "John" and 30. Class methods

Class methods are functions that an object can call. They are defined as functions within the class and declared using the def

keyword.

Example:

class Person: def get_info(self): return f"{self.name} is {self.age} years old."

This code creates a method called

get_info()

that returns the

name and age properties of the object. Class attribute

Class attributes are data members associated with the class itself. They are stored in classes, not in individual objects.

Example:

class Person: species = "Homo sapiens"

This code creates a class attribute called

species

that stores the species of all

Person objects. inherit

Inheritance allows a class to inherit its properties and methods from another class (parent class). Subclasses have all the functionality of the parent class and can define their own unique properties and methods.

Example:

class Employee(Person): def get_salary(self): return 1000

This code creates a subclass named

Employee

that inherits the

name and age properties from the Person class. A get_salary() method is also defined to return the employee's salary. Polymorphism

Polymorphism allows objects of different types with the same parent class to respond differently to the same method. It allows developers to write more flexible and reusable code.

Example:

class Animal:
def make_sound(self):
raiseNotImplementedError()

class Dog(Animal):
def make_sound(self):
return "Woof!"

class Cat(Animal):
def make_sound(self):
return "Meow!"

This code creates a Animal base class that has a make_sound() method. Then create two subclasses Dog and Cat, both of which override the make_sound() method and return different sounds.

Understanding classes and objects in Python is critical to developing reusable, flexible, and easy-to-maintain code. By mastering these concepts, developers can create complex applications and improve the quality of their code.

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