Python Coding challenge - Day 1013| What is the output of the following Python Code?

 

Code Explanation:

1. Defining the class

class Cache:

This defines a class named Cache.

The class will dynamically create attributes when they are first accessed.

2. Defining __getattr__

    def __getattr__(self, name):

__getattr__ is a special method.

It is called only when an attribute is NOT found in:

the instance dictionary, or

the class.

name is the attribute name being accessed.

3. Creating the attribute dynamically

        self.__dict__[name] = len(name)

This line adds a new attribute to the instance.

The attribute name is name.

The value stored is len(name) (length of the attribute name).

This is called lazy initialization or caching.

4. Returning the value

        return len(name)

The method returns the computed value.

So the first access gives back the same value that was stored.

5. Creating an instance

c = Cache()

An object c of class Cache is created.

Initially, c.__dict__ is empty.

6. First attribute access

print(c.abc, c.abc)

🔹 First c.abc

Python looks for abc in c.__dict__ → not found.

Python looks in the class Cache → not found.

__getattr__(self, "abc") is called.

len("abc") → 3.

abc is stored in c.__dict__ as:

{"abc": 3}

The value 3 is returned.

🔹 Second c.abc

Python finds abc directly in c.__dict__.

__getattr__ is not called.

The cached value 3 is returned instantly.

✅ Final Output

3 3

900 Days Python Coding Challenges with Explanation