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Computer science · lesson 4 of 4

Lists, dictionaries and iteration

An ordered mutable collection addressed by position.

University8 practice questionsNotes + worked examples
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Learn the ideas

Prerequisites: Basic computer literacy.

List

An ordered mutable collection addressed by position.

Dictionary

A mapping from keys to values.

Index

A position used to access an item in a sequence.

Traversal

Visiting items in a collection systematically.

Worked examples

Example 1

Which term best matches this description: An ordered mutable collection addressed by position.

List is the matching concept in this lesson.

List

Example 2

Which term best matches this description: A mapping from keys to values.

Dictionary is the matching concept in this lesson.

Dictionary

Check your understanding

8 questions

Decimals or fractions are accepted for numeric answers. Proofs and written responses use sample answers and require human marking. This is practice, not a protected examination.

1 Which term best matches this description: An ordered mutable collection addressed by position.

Show answer and explanation

List

List is the matching concept in this lesson.

2 Which term best matches this description: A mapping from keys to values.

Show answer and explanation

Dictionary

Dictionary is the matching concept in this lesson.

3 Which concept would you apply first in a situation where a position used to access an item in a sequence.

Show answer and explanation

Index

The scenario directly calls for Index.

4 Name the concept described as: Visiting items in a collection systematically.

Show answer and explanation

Traversal

The intended concept is Traversal.

5 Which statement about List is most accurate?

Show answer and explanation

An ordered mutable collection addressed by position.

The definition in the lesson notes gives the required condition.

6 Explain one important difference between List and Dictionary.

Sample answer and marking guidance

List: An ordered mutable collection addressed by position. Dictionary: A mapping from keys to values.

Credit a clear distinction using both definitions and an appropriate example if supplied.

7 Give a short example showing how Index would be used in practice.

Sample answer and marking guidance

A valid example should demonstrate this idea: A position used to access an item in a sequence.

Credit a relevant scenario that applies the concept rather than merely naming it.

8 Summarize why Traversal matters in the lesson “Lists, dictionaries and iteration”.

Sample answer and marking guidance

Traversal matters because Visiting items in a collection systematically.

Credit the core purpose, scope and any important limitation from the notes.

Further reading and review references

These are reference links, not copied exercises, institutional endorsement or proof of independent review.