Previous: UML Class Diagram

Object-oriented programming (OOP) involves the use of objects to create programs. An object represents an entity in the real world that can be distinctly identified. For example, a student, a circle, a button... An object has a unique identity, state, and behavior.

Object consists of: Data fields: state, properties, attributes; Methods: behavior, actions.

Object-oriented programming enables you to develop large-scale software and GUIs effectively. It is also easy to design, implement, test, debug, update.

The four pillars of OOP: abstraction, encapsulation, inheritance, polymorphism.

In programming languages, the class is a Data Type, a Blueprint, or a Template. The object is the working instance of the class, and one or more variables can hold a reference to an instance.

An object is an instance of a class, and you can create many instances of a class. Creating an instance of a class is referred to as instantiation. The terms object and instance are often used interchangeably. An object is an instance and an instance is an object.

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In Summary:

• Class: A built-in method in Python used to define an object;
• Instances: Another way to refer to the objects of a class;
• The functions defined inside a class are called the methods of the object. </aside>

__init__() is the constructor method in Python, which initializes the object’s attributes with default or specified values. When a new instance is created, this __init__()method is called.

__del__() is the destructor method in Python, which automatically destroys the object when it no longer has any references.

Object Example: Human class with name, age, gender, city; Methods: can walk(), can sleep(), can speak(), can eat().

Ed Corner, 32, Male, New York —> This is an instance of the Human class.

# Initialize the Class

class Human:
    def __init__(self, name, age, gender, city):  # initializes the attributes
        print("This is an instance of the Human Class")
        self.name = name
        self.age = age
        self.gender = gender
        self.city = city

def main():
    # Create an instance Student
    p1 = Human("Ed Corner", 32, "Male", "New York")
    print(p1)

main()

Output:

This is an instance of the Human Class
<__main__.Human object at 0x10cecce90>