Python Coding challenge - Day 1267| What is the output of the following Python Code?

 

Code Explanation:

1️⃣ Creating an Empty List

funcs = []

An empty list named funcs is created.

It will store the lambda functions.

Initially:

funcs = []

2️⃣ Starting the for Loop

for i in range(3):

range(3) produces:

0, 1, 2

So the loop runs three times:

First iteration  → i = 0

Second iteration → i = 1

Third iteration  → i = 2

3️⃣ Creating the Lambda Function

funcs.append(lambda: i)

A lambda function is created and added to the list.

The lambda is equivalent to:

def f():

    return i

Important Trick ⚠️

The lambda does not immediately store the current value of i.

It remembers the variable i itself.

This is called late binding.

4️⃣ First Iteration

When:

i = 0

this function is added:

lambda: i

But it does not permanently store 0.

The function keeps a reference to the variable i.

5️⃣ Second Iteration

Now:

i = 1

Another lambda is added.

Again, it refers to the same loop variable i.

So the list now contains two functions that both refer to i.

6️⃣ Third Iteration

Now:

i = 2

A third lambda is added.

Again, it refers to the same variable i.

After the loop finishes:

i = 2

This is the key to the output.

7️⃣ Calling the Functions

[f() for f in funcs]

This calls each lambda in the list.

There are three functions:

f₁()

f₂()

f₃()

But all three functions look up the value of the same variable i.

After the loop, i is:

2

Therefore:

f₁() → 2

f₂() → 2

f₃() → 2

8️⃣ List Comprehension Result

The list comprehension collects those results:

[2, 2, 2]

🎯 Final Output

[2, 2, 2]

400 Days Python Coding Challenges with Explanation