Python Coding challenge - Day 190 | What is the output of the following Python Code?

 

Code:

class MyClass:

    x = 1

p1 = MyClass()

p2 = MyClass()

p1.x = 2

print(p2.x)

Solution and Explanation:

Let's break down the code:

class MyClass:

    x = 1

p1 = MyClass()

p2 = MyClass()

p1.x = 2

print(p2.x)

Class Definition (MyClass):

Here, a class named MyClass is defined.

Inside the class, there's a class variable x initialized with the value 1.

Object Instantiation:

Two instances of the class MyClass are created: p1 and p2.

Instance Variable Assignment (p1.x = 2):

The instance variable x of p1 is set to 2. This doesn't modify the class variable x but creates a new instance variable x for p1.

Print Statement (print(p2.x)):

This statement prints the value of x for the instance p2. Since p2 hasn't had its x modified, it still references the class variable x which has a value of 1. Thus, it prints 1.

Let's dissect the crucial part, p1.x = 2:

When p1.x = 2 is executed, Python first checks if p1 has an attribute x. If not, it looks for it in the class definition.

Since p1 didn't have an x attribute, Python creates one for p1, setting its value to 2.

This doesn't change the class variable x itself or affect other instances of MyClass, such as p2. Each instance of the class maintains its own namespace of attributes.

Hence, when print(p2.x) is called, it prints 1 because p2 still references the class variable x, which remains unaffected by the modification of p1.x.