Python object

In Python, an object is an instance of a class, which acts as a blueprint for creating objects. Each object contains data (variables) and methods to operate on that data. Python is object-oriented, meaning it focuses on objects and their interactions. For a better understanding of the concept of objects in Python. Let's consider an example, many of you have played CLASH OF CLANS, So let's assume base layout as the class which contains all the buildings, defenses, resources, etc. Based on these descriptions we make a village, here the village is the object in Python.

Creating an object

When creating an object from a class, we use a special method called the constructor, defined as __init__(), to initialize the object's attributes. Example:

class Car:
    def __init__(self, model, price):
        self.model = model
        self.price = price

Audi = Car("R8", 100000)
print(Audi.model) 
print(Audi.price)  

R8
100000

Explanation: Car class defines a blueprint for car objects. The __init__() constructor initializes the model and price attributes, using self to refer to the current object. When Audi = Car("R8", 100000) is executed, "R8" is assigned to model and 100000 to price. These attributes are accessed via dot notation, like Audi.model and Audi.price.

Accessing class members

In Python, you can access both instance variables and methods of a class using an object. Instance variables are unique to each object, while methods define the behavior of the objects. Below are examples demonstrating how to access and interact with class members:

Example 1: In this example, we use methods to access and modify the car's attributes.

class Car:
    def __init__(self, model):
        self.model = model

    def setprice(self, price):
        self.price = price

    def getprice(self):
        return self.price

Audi = Car("R8")
Audi.setprice(1000000)
print(Audi.getprice())

1000000

Explanation: Car class defines a blueprint for car objects with a constructor (__init__()) to initialize the model attribute. The setprice() method assigns a price and getprice() retrieves it. When Audi = Car("R8") is executed, the model is set to "R8", the price is set using setprice() and the price is accessed with getprice().

Example 2: In this example, we create multiple car objects and access the model and price attributes directly using the objects, without the need for methods.

class Car:
    vehicle = 'Car'

    def __init__(self, model, price):
        self.model = model
        self.price = price

Audi = Car("R8", 100000)
BMW = Car("I8", 10000000)

print(Audi.model, Audi.price)
print(BMW.model, BMW.price)

R8 100000
I8 10000000

Explanation: Car class defines a blueprint with a class variable vehicle and a constructor to initialize model and price. When Audi = Car("R8", 100000) and BMW = Car("I8", 10000000) are executed, the attributes are set and accessed directly, like Audi.model and Audi.price.

Self keyword in Python objects

In Python objects, the self keyword represents the current instance of the class. It is automatically passed to instance methods and is used to access and modify the object's own attributes and methods. By using self, each object can maintain its own separate state, ensuring that operations are performed on the correct instance. Example:

class Test:
    def __init__(self, a, b):
        self.country = a
        self.capital = b

    def fun(self):
        print("Capital of " + self.country + " is " + self.capital)

x = Test("India", "Delhi")
x.fun()

Capital of India isDelhi

Explanation: Test class uses the __init__() constructor to initialize the country and capital attributes with self. When x is created with "India" and "Delhi", x.country and x.capital are set. The fun() method then accesses these attributes via self .

Deleting an object

You can delete objects, variables or object properties using the del keyword. This removes the reference to the object or attribute from memory, allowing Python's garbage collector to reclaim the memory if no other references exist. Example:

class Car:
    def __init__(self, brand, model):
        self.brand = brand
        self.model = model
        
Audi = Car("Audi", "A6") # creating obj

del Audi # deleting obj
print(Audi.brand)

Output

Hangup (SIGHUP)
Traceback (most recent call last):
  File "/home/guest/sandbox/Solution.py", line 10, in <module>
    print(Audi.brand)
          ^^^^
NameError: name 'Audi' is not defined

Explanation: After creating the Audi object, the del keyword deletes it. Attempting to access Audi.brand afterward results in an error because the object no longer exists.

Related Articles:

• Python Tutorial
• Python Classes and Objects
• Introduction of Object Oriented Programming
• __init__ in Python
• self in Python class