Can you explain the basic principles and concepts of object-oriented programming?

Object-oriented programming (OOP) is based on several key principles:

• Encapsulation — combining data and methods that operate on that data into a single object, which allows hiding internal implementation details and protecting data.
• Inheritance — a mechanism that allows creating new classes based on existing ones, inheriting their properties and methods, which promotes code reuse.
• Polymorphism — the ability of objects of different classes to respond to the same messages (method calls) in different ways.
• Abstraction — highlighting the essential characteristics of an object while hiding implementation details.

Example in Python:

class Animal:
    def speak(self):
        pass

class Dog(Animal):
    def speak(self):
        return "Woof"

class Cat(Animal):
    def speak(self):
        return "Meow"

animals = [Dog(), Cat()]
for animal in animals:
    print(animal.speak())  # Polymorphism: same method, different behavior