6. Object-Oriented Programming in Python

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Object-oriented programming (OOP) is a programming paradigm that offers a way to structure programs so that properties and behaviors are grouped into individual objects. Python is an object-oriented programming language and therefore an important part of the Python with Lambda and API Gateway for backend development course.

To begin with, it is important to understand what an object is in Python. In Python, everything is an object. This includes numbers, strings, lists, dictionaries and even functions. Every object in Python has a type (like string or list) and data. The object type defines the possible values ​​and operations (such as "add" for numbers or "concatenate" for strings).

Object-oriented programming in Python involves creating classes, which are essentially templates for creating objects. A class defines the attributes and methods that characterize any object that is an instance of that class.

An attribute is a characteristic of an object. For example, if we were modeling a car as an object, some possible attributes could include color, model, and brand. A method is an operation that we can perform with the object. For example, a car can accelerate, brake or turn.

To define a class in Python, we use the 'class' keyword, followed by the class name (which, by convention, starts with a capital letter). For example, to create a Car class, we could write:

class Car:
    pass

This defines a Car class, but it still has no attributes or methods. To add attributes, we can use the special __init__ method. This method is called automatically when we create a new object from the class. For example:

class Car:
    def __init__(self, color, model, brand):
        self.color = color
        self.model = model
        self.brand = brand

Here, the 'self' parameter is a reference to the current object - it's how the object refers to itself. The other parameters (color, model, brand) are the attributes we want to add to the object. Now, we can create a new car like this:

my_car = Car('red', 'sedan', 'Toyota')

To add methods to a class, we define a new function within the class. For example, we could add an 'accelerate' method to our Car class:

class Car:
    def __init__(self, color, model, brand):
        self.color = color
        self.model = model
        self.brand = brand

    def accelerate(self):
        print('Speeding up...')

Now, we can call the accelerate method on any Car object:

my_car = Car('red', 'sedan', 'Toyota')
my_car.accelerate() # Prints: Accelerating...

Object-oriented programming in Python also supports concepts such as inheritance (where one class can inherit attributes and methods from another), encapsulation (restricting direct access to some of the object's attributes and methods), and polymorphism (where a class may share the same method name, but behaves differently depending on the class).

In summary, object-oriented programming in Python is a fundamental part of effective backend development. It allows you to structure your code in a logical and reusable way, making it easier to maintain and extend your programs.

Next page of the Free Ebook:

206.1. Object-Oriented Programming in Python: Introduction to Object-Oriented Programming