Python Coding challenge - Day 1167| What is the output of the following Python Code?

 

Code Explanation:

🔹 1. Importing defaultdict

from collections import defaultdict

✅ Explanation:

defaultdict is imported from Python's collections module.

It works like a normal dictionary but automatically creates default values for missing keys.

🔹 2. Creating a defaultdict

d = defaultdict(int)

✅ Explanation:

A defaultdict object is created.

int is used as the default factory.

⚠️ Important:

When a missing key is accessed:

int()

is called automatically.

Result:

0

So every new key starts with value:

0

🔹 3. First Update

d["a"] += 1

🔍 What happens internally?

Python tries to read:

d["a"]

But key "a" does not exist.

defaultdict Action

It automatically creates:

d["a"] = 0

Current dictionary:

{'a': 0}

Now Increment

0 + 1

Result:

1

Dictionary becomes:

{'a': 1}

🔹 4. Second Update

d["b"] += 2

🔍 What happens?

Python checks:

d["b"]

Key "b" does not exist.

defaultdict Creates Default

d["b"] = 0

Current dictionary:

{

    'a': 1,

    'b': 0

}

Add 2

0 + 2

Result:

2

Dictionary becomes:

{

    'a': 1,

    'b': 2

}

🔹 5. Converting to Normal Dictionary

print(dict(d))

✅ Explanation:

d is a defaultdict.

dict(d) converts it into a normal dictionary.

Result:

{

    'a': 1,

    'b': 2

}

🎯 Final Output

{'a': 1, 'b': 2}