Python Coding challenge - Day 905| What is the output of the following Python Code?

 

Code Explanation:

1. Class Definition

class Lock:

Explanation:

A class named Lock is created.

This class will represent an object that has a private value (key).

2. Constructor Method (__init__)

def __init__(self):

Explanation:

__init__ is a constructor.

It runs automatically when an object of the class is created.

self refers to the current object.

3. Private Instance Variable

self.__key = 123

Explanation:

__key is a private instance variable.

Because it starts with double underscore (__), Python applies name mangling.

Internally, Python renames it as:

_Lock__key

This prevents accidental access from outside the class.

4. Object Creation

l = Lock()

Explanation:

An object l of class Lock is created.

During object creation, the constructor runs and:

self.__key = 123 is stored internally as _Lock__key.

5. Accessing Private Variable Using Name Mangling

print(l._Lock__key)

Explanation:

Direct access like l.__key is not allowed.

But Python allows access using name-mangled form:

_ClassName__variableName

Here:

_Lock__key

So the value 123 is printed.

FINAL OUTPUT

123

400 Days Python Coding Challenges with Explanation