Python Coding challenge - Day 389| What is the output of the following Python Code?

 

Code Explanation:

1. Understanding Descriptors

A descriptor is a class that defines special methods (__get__, __set__, __delete__) to control attribute access in another class.

Here, Descriptor implements __get__, meaning it controls what happens when its attribute is accessed.

2. Defining the Descriptor Class

class Descriptor:

    def __get__(self, obj, objtype=None): 

        return 42

The __get__ method is triggered whenever an instance of a class accesses an attribute that is a descriptor.

It takes three parameters:

self → The descriptor instance itself.

obj → The instance of the class where the descriptor is being accessed (e.g., t of Test).

objtype → The class type of the instance (i.e., Test).

The method always returns 42, regardless of the object or class.

3. Defining and Using the Test Class

class Test:

    value = Descriptor()

value is an instance of Descriptor, meaning it is a data descriptor for the Test class.

Since value is a class attribute, any access to Test().value triggers Descriptor.__get__.

4. Accessing the Descriptor

t = Test()

print(t.value)

When t.value is accessed, Python does not return a normal instance attribute. Instead:

It detects that value is a descriptor.

Calls Descriptor.__get__(self=Descriptor instance, obj=t, objtype=Test).

The __get__ method returns 42.

Final Output:

42