A developer is working with a large dataset and needs to create a list of all numbers that are both prime and palindromic. They have a helper function `is_prime(n)`. They want to use a list comprehension, but they are concerned about performance. Which approach is most efficient?

[n for n in range(1000) if is_prime(n) and n % 2 != 0]

[n for n in range(1000) if str(n) == str(n)[::-1] and is_prime(n)]

[n for n in range(1000) if is_prime(n) and str(n) == str(n)[::-1]]

[n for n in range(1000) if str(n) == str(n)[::-1] and n % 2 != 0]

Select all that apply. A developer wants to create a list of all even numbers from 0 to 20 that are also divisible by 4. Which of the following list comprehensions achieve this?

[x for x in range(21) if x % 4 == 0 and x % 2 == 0]

[x for x in range(21) if x % 2 == 0 and x % 4 == 0]

[x for x in range(21) if x % 2 == 0]

[x for x in range(21) if x % 4 == 0]

A developer is trying to flatten a list of lists, but they also want to remove any duplicate values. They want to use a list comprehension, but they are aware that list comprehensions cannot directly remove duplicates. Which approach is the most efficient?

Use a for loop with a set to track seen elements.

Use a list comprehension to flatten, then convert to a set and back to a list.

Use a list comprehension with a condition that checks if the element has already been added.

Use a nested list comprehension that includes a set to track seen elements.

A developer is working with a list of strings and wants to create a list of all strings that contain the letter 'a' and have length greater than 3. They also want to ensure the code is case-insensitive. Which comprehension is correct?

[s for s in strings if len(s) > 3 and 'a' in s.lower()]

[s for s in strings if 'a' in s.lower() and len(s) > 3]

[s for s in strings if 'a' in s and len(s) > 3]

[s for s in strings if s.lower().count('a') > 0 and len(s) > 3]

Python InstitutePCAP - Certified Associate Python Programmer

Domain 5Objective 1

PCAP-31-03 5.1 Build Complex Lists Using List Comprehensions PCAP-31 Practice Questions (Page 3)

Part of the Miscellaneous (List Comprehensions, Lambdas, Closures, I/O) domain, which accounts for 22% of the PCAP-31 exam. Python Institute does not publish an official question count, but from its 65-minute exam (~25–45 total, ~6–10 in this domain), expect 1–2 from this objective — we provide 43 practice questions to prepare you well beyond it. (estimate)

43questions here

9free pages

2concepts

22%of the exam

Questions 11–14

11expert · hard
A developer is working with a large dataset and needs to create a list of all numbers that are both prime and palindromic. They have a helper function `is_prime(n)`. They want to use a list comprehension, but they are concerned about performance. Which approach is most efficient?
Select an answer first
12expert · hard · select all that apply
Select all that apply. A developer wants to create a list of all even numbers from 0 to 20 that are also divisible by 4. Which of the following list comprehensions achieve this?
Select an answer first
13expert · hard
A developer is trying to flatten a list of lists, but they also want to remove any duplicate values. They want to use a list comprehension, but they are aware that list comprehensions cannot directly remove duplicates. Which approach is the most efficient?
Select an answer first
14expert · hard
A developer is working with a list of strings and wants to create a list of all strings that contain the letter 'a' and have length greater than 3. They also want to ensure the code is case-insensitive. Which comprehension is correct?
Select an answer first

Finished these 4 questions?

Review the revealed explanations, or continue through the curriculum.

Next 5 questions →Back to PCAP-31

Free Basic Practice is a study aid with revealable answers — not a scored exam. Examers.io is independent and not affiliated with or endorsed by Python Institute. “PCAP-31” is a trademark of its owner, used for identification only.