PCEP Control Flow, Loops, Lists and Logic Practice Question

What is the output of the code?

numbers = [1, 2, 3, 4] result = [x**2 for x in numbers if x % 2 == 0]

print(result)

⚠ Common exam trap

Python Institute often tests the distinction between the filter condition and the transformation expression, so the trap here is that candidates may confuse the filtered elements with the transformed output, leading them to pick the original even numbers (option A) or a mix (option D).

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

[4, 16]

The list comprehension `[x**2 for x in numbers if x % 2 == 0]` iterates over `numbers`, filters for even numbers (2 and 4) using the condition `x % 2 == 0`, and squares each selected element. Squaring 2 gives 4, squaring 4 gives 16, so the result is `[4, 16]`. Option B is correct.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
[2, 4]
Why it's wrong here
These are the even numbers, not their squares.
✓
[4, 16]
Why this is correct
Correct squares of even numbers.
✗
[1, 9]
Why it's wrong here
Squares of odd numbers (1 and 3).
✗
[2, 4, 16]
Why it's wrong here
Includes incorrect item 2.

Go deeper

PCEP Control Flow, Loops, Lists and Logic Practice Question

Why each option matters

Option-by-option breakdown

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