Python Coding challenge - Day 1179| What is the output of the following Python Code?

 

Code Explanation:

🔹 1. Creating a List

nums = [1, 2, 3, 4]

✅ Explanation:

A list named nums is created.

Contents:

[1, 2, 3, 4]

Current state:

nums

 ↓

[1, 2, 3, 4]

🔹 2. Calling filter()

result = filter(

✅ Explanation:

filter() is a built-in Python function.

Its job:

Keep elements that satisfy a condition

Remove elements that don't

Syntax:

filter(function, iterable)

🔹 3. Lambda Function

lambda x: x % 2 == 0

✅ Explanation:

This is an anonymous function.

Equivalent to:

def check(x):

    return x % 2 == 0

Rule:

If x is even → True

If x is odd  → False

🔹 4. Understanding the Condition

x % 2 == 0

✅ Explanation:

% means modulus (remainder).

Examples:

2 % 2

Result:

0

3 % 2

Result:

1

Condition:

x % 2 == 0

means:

Is x divisible by 2?

If yes:

True

Otherwise:

False

🔹 5. First Iteration

Current value:

x = 1

Check:

1 % 2 == 0

Result:

False

So:

1 is discarded

🔹 6. Second Iteration

Current value:

x = 2

Check:

2 % 2 == 0

Result:

True

So:

2 is kept

🔹 7. Third Iteration

Current value:

x = 3

Check:

3 % 2 == 0

Result:

False

So:

3 is discarded

🔹 8. Fourth Iteration

Current value:

x = 4

Check:

4 % 2 == 0

Result:

True

So:

4 is kept

🔹 9. Result of Filter

After checking all elements:

Kept values:

2

4

Filtered object contains:

filter object

Not a list yet.

🔹 10. Converting to List

list(result)

✅ Explanation:

Converts filter object into a list.

Before:

<filter object at 0x...>

After:

[2, 4]

🔹 11. Printing Result

print(list(result))

prints:

[2, 4]

🎯 Final Output

[2, 4]

500 Days Python Coding Challenges with Explanation