Quick Answer
The correct answer is that it returns a new reversed string. This is because strings in Python are immutable, meaning they cannot be changed in place; the slicing operation s[::-1] creates a brand new string by stepping through the original sequence from end to beginning with a step of -1. On the Certified Associate Python Programmer PCAP exam, this question tests your understanding of both string immutability and extended slicing syntax, often appearing as a straightforward concept check that many candidates overthink. A common trap is assuming the function modifies the original string or that it fails on empty strings—neither is true, as slicing gracefully handles any sequence, including empty ones. To remember this, think of the slice notation as [start:stop:step]; a negative step reverses direction, and since strings are immutable, a copy is always returned.
This PCAP practice question tests your understanding of strings. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A developer writes a function to reverse a string: def reverse_str(s): return s[::-1]. Which of the following statements about this function is true?
It only works for strings with even length
Why wrong: Incorrect: Reversal works for any length.
It returns a new reversed string
Correct: s[::-1] creates a new reversed string without modifying the original.
It modifies the original string
Why wrong: Incorrect: Strings are immutable; slicing creates a new string.
It raises an error if s is empty
Why wrong: Incorrect: Slicing an empty string returns an empty string without error.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
It returns a new reversed string
Strings are immutable in Python, so slicing returns a new string. The step -1 reverses the sequence. The function works for any string, including empty strings.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
It only works for strings with even length
Why it's wrong here
Incorrect: Reversal works for any length.
It returns a new reversed string
Why this is correct
Correct: s[::-1] creates a new reversed string without modifying the original.
Related concept
Read the scenario before looking for a memorised answer.
It modifies the original string
Why it's wrong here
Incorrect: Strings are immutable; slicing creates a new string.
It raises an error if s is empty
Why it's wrong here
Incorrect: Slicing an empty string returns an empty string without error.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Identify which PCAP exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Strings — This question tests Strings — Read the scenario before looking for a memorised answer..
The correct answer is: It returns a new reversed string — Strings are immutable in Python, so slicing returns a new string. The step -1 reverses the sequence. The function works for any string, including empty strings.
Identify which PCAP exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
This PCAP practice question is part of Courseiva's free Python Institute certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCAP exam.
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