Object Oriented Programming (OOP)
OOP has self-contained objects containing both the programming routine/procedureA section of computer code that performs a specific task. and the data being processed. These objects interact by sending data to one another.
In Object Oriented Programming, written classes represent and create real world objects. Class attributes and procedures are known as methods.
The four pillars of object-oriented programming are:
- Inheritance: child classes inherit data and behaviours from the parent class
- Encapsulation: containing information in an object, exposing only selected information
- Abstraction: only exposing high-level public methods for accessing an object
- Polymorphism: many methods can do the same task
Class
The class is the blueprint, or template, that defines what an object is. This includes the type of data an object can hold, its initial value and how the object behaves.
From classes, we can create instances. An instance is an object created from a particular class.
If we have a class called Dog, we can create as many instances (Dog1, Dog2, BigDog, SmellyDog) as we like – all with different ages and names.
For example, Dog1 might be an instance of the Dog class:
class Dog: #creates the Dog class def __init__(self, name, age): self.name = name #self prefix allows all methods to access attributes self.age = age Dog1 = Dog('Bruce', 3) #creates object Dog1 - name Bruce, age 3Attributes
Attributes are characteristics of an object. A special method called __init__() is used to initialize the attributes of an object. The Dog class has two attributes (name and age).
Methods
Methods are functions defined inside the body of a class. They are used to perform operations with the attributes of our objects. For example:
class Dog: def __init__(self, name, age): self.name = name self.age = age def bark(self): print(self.name + 'is barking')# Dog1 = Dog('Bruce')
Dog1.bark()This will output: Bruce is barking
