Constructor in Python
Constructor, as the name, suggests that is constructing something. or, in other words, we can say it is the first step of any task.
Constructors are generally used for initializing an object. In other languages, we need to make a method with the same name as the class, to declare a constructor. But in Python, the __init__() method is called the constructor and is always called when an object of the class is created.
Syntax of declaration of constructor in Python
def __init__(self):
Types of constructor in Python
Basically, there are two types of constructors in Python –
- Default Constructor
- Parameterized Constructor
Default Constructor
The default constructor is a constructor that is automatically invoked even if the programmer doesn’t make any constructors inside the class it creates. Its definition has only one argument which is the reference to the instance being constructed.
We will understand this with the help of the example given below –
class CrazyCoder:
def __init__(self):
self.code = "Yuvayana Tech"
def print_code(self):
print(self.code)
obj = CrazyCoder()
obj.print_code()
Output –
Yuvayana Tech
Parameterized Constructor in Python
A constructor with parameters passed as arguments is called a parameterized constructor. The parameterized constructor takes its first argument as a reference to the instance being constructed known as self and the rest of the arguments are provided by the programmer.
We will understand this better with the help of the example given below –
class Addition:
num1 = 0
num2 = 0
answer = 0
def __init__(self, f, s):
self.num1 = f
self.num2 = s
def display(self):
print("Num1 number = " + str(self.num1))
print("Num2 number = " + str(self.num2))
print("Addition of two numbers = " + str(self.answer))
def calculate(self):
self.answer = self.num1 + self.num2
obj = Addition(500, 600)
obj.calculate()
obj.display()
Output –
Num1 number = 500 Num2 number = 600 Addition of two numbers = 1100
Destructor in Python
Destructors are the last code that runs when the object of a class gets destroyed. In python, destructors are not much needed as in C++ and Java. Because Python by-default provides the garbage collector which handles the memory management.
Like C++ and Java, we don’t need to create a function with the same name. But here, we have a __del__(self) method to do this.
Syntax for declaration of destructor in python
def __del__(self):
class Animals:
def __init__(self):
print('The class called Animals is CREATED.')
def __del__(self):
print('The destructor is called for deleting the Animals.')
object = Animals()
del object
Output –
The class called Animals is CREATED.
The destructor is called for deleting the Animals.
So, in this article, we learned about the concepts of constructors used to initialize objects and destructors which are used for memory management.
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