- A
set
Set is unordered and contains only unique elements.
- B
tuple
Why wrong: Tuple is ordered and allows duplicates.
- C
list
Why wrong: List is ordered and allows duplicates.
- D
dict
Why wrong: Dict is an associative array, not a collection of unique elements.
Question 739 of 1,000
200-901 Software Development and Design Practice Question
This 200-901 practice question tests your understanding of software development and design. 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.
In Python, which data type is used to represent an unordered collection of unique elements?
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
✓
set
In Python, a set is the correct data type for representing an unordered collection of unique elements. Sets automatically enforce uniqueness by using a hash table internally, so duplicate values are ignored upon insertion. This makes them ideal for operations like membership testing and deduplication, where order is irrelevant.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
set
Why this is correct
Set is unordered and contains only unique elements.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
tuple
Why it's wrong here
Tuple is ordered and allows duplicates.
- ✗
list
Why it's wrong here
List is ordered and allows duplicates.
- ✗
dict
Why it's wrong here
Dict is an associative array, not a collection of unique elements.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse a set with a list or tuple because they think 'collection of items' implies order or mutability, but Cisco specifically tests the requirement for uniqueness and lack of order, which only the set satisfies.
Detailed technical explanation
How to think about this question
Under the hood, Python's set uses a hash table similar to dict keys, providing O(1) average-time complexity for add, remove, and membership checks. A subtle behavior is that sets require all elements to be hashable (immutable), so you cannot store a list or another set inside a set, but you can store a frozenset. In real-world scenarios, sets are commonly used to remove duplicates from a list (e.g., `unique_items = list(set(my_list))`) or to perform efficient mathematical set operations like union, intersection, and difference.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the 200-901 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this 200-901 question test?
Software Development and Design — This question tests Software Development and Design — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: set — In Python, a set is the correct data type for representing an unordered collection of unique elements. Sets automatically enforce uniqueness by using a hash table internally, so duplicate values are ignored upon insertion. This makes them ideal for operations like membership testing and deduplication, where order is irrelevant.
What should I do if I get this 200-901 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
This 200-901 practice question is part of Courseiva's free Cisco 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 200-901 exam.
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