Classes

Class

A class outlines the properties and methods for creating objects. You can think of a class as a blueprint. When an object is created from a class, the resulting object is called an instance of a class.

Object Oriented Programming

Object-Oriented Programing (OOP) focuses on objects that contain specific data and functions together. OOP is a style of programming that focuses on creating reusable patterns of code. This is in contract with procedural programming which focuses on explicit sequenced instructions.

Properties

Properties are data that define your object.

Methods

Methods, also known as behaviors, are operations that define your object.

Dot Notation

Dot notation indicates that you’re accessing data or methods for a particular object. When you use dot notation, you’re telling Python that you want to either run a particular operation on or access a particular property of an object.

init Method

The __init__ method is usually the first method inside a class definition. A method is a function defined in a class. It is also called the Constructor.

self

When defining an instance method, the first parameter of the method should always be self. To define a data attribute of the object, you use a variable named self with a dot after it.

Example 1

Create a class named Student that passes in a parameter named object.

Create an init method that passes in self and name.

Set self name to name.

In the main function, create an object named s1. Pass your name as an argument to s1.

Print the name of the object s1.

class Student():
    def __init__(self, name):
        self.name = name

def main():
   sam = Student("Sam")
   print(sam.name)

Example 2

Add an additional property of the Student object.

In the init method, add the parameter town.

Set self town to town.

In the main function, create an object named s1. Pass your town as an argument to s1.

Print the town of the object s1.

class Student():
    def __init__(self, name):
        self.name = name
        self.town = town

def main():
   sam = Student("Sam", "Paterson")
   print(sam.name)
   print(sam.town)

Example 3

Add a behavior to the Student object. In the Student class, create a method named hello. Print Hello and the object’s name and town.

class Student():
    def __init__(self, name):
        self.name = name
        self.town = town

def hello(self):
    print("Hello ", self.name)


def main():
   sam = Student("Sam", "Paterson")
   print(sam.name)
   print(sam.town)
   sam.hello()