Constructor

Introduction

In Python, a constructor is a special method that is automatically called when an object of a class is created. It is defined using the __init__() method. The constructor initializes the object's attributes and performs any setup required when the object is created.

class ClassName:
    def __init__(self, parameters):
        # Initialize attributes here
        self.attribute = parameters

Key Points:

1. Special Method: The constructor method is always named __init__.
2. First Parameter: The first parameter of __init__ is always self, which refers to the instance of the class being created.
3. Optional Parameters: Constructors can accept additional parameters for initializing specific attributes.
4. Automatic Call: The constructor is invoked automatically when an object is instantiated.

Example 1: Basic Constructor

class Person:
    def __init__(self, name, age):
        self.name = name  # Initialize name attribute
        self.age = age    # Initialize age attribute

# Create an instance of the Person class
person1 = Person("Jasmeet", 30)

print(person1.name)  # Output: Jasmeet
print(person1.age)   # Output: 30

Example 2: Default Values in Constructor

class Car:
    def __init__(self, make, model, year=2020):  # Default value for year
        self.make = make
        self.model = model
        self.year = year

car1 = Car("Toyota", "Corolla")
print(car1.year)  # Output: 2020

car2 = Car("Tesla", "Model S", 2022)
print(car2.year)  # Output: 2022

Example 3: Constructor with No Parameters

class SimpleClass:
    def __init__(self):
        self.message = "Hello, World!"

obj = SimpleClass()
print(obj.message)  # Output: Hello, World!

Advantages of Constructors:

• Encapsulation: Helps initialize the object's attributes at the time of creation.
• Ease of Use: Automatically sets up the object, making it easier to work with classes.