Iterating enum cases with CaseIterable in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the CaseIterable protocol do in Swift enums?

It allows an enum to provide a collection of all its cases, so you can easily loop through them.

beginner

How do you make an enum conform to CaseIterable?

Add CaseIterable after the enum name, like enum Direction: CaseIterable { ... }.

beginner

How can you access all cases of a CaseIterable enum?

Use the static property allCases, for example: Direction.allCases returns a collection of all cases.

intermediate

What type is allCases in a CaseIterable enum?

It is a collection (usually an array) of all enum cases, with type [EnumName].

beginner

Why is CaseIterable useful when working with enums?

It lets you easily loop over all enum cases without manually listing them, which saves time and reduces errors.

How do you declare an enum named Color that supports iterating all its cases?

A enum Color: CaseIterable { case red, green, blue }

B enum Color { case red, green, blue }

C enum Color: Iterable { case red, green, blue }

D enum Color: IterableCase { case red, green, blue }

Only CaseIterable is the correct protocol to enable iteration over enum cases.

What does Color.allCases return if Color conforms to CaseIterable?

A An array of all Color enum cases

B A single Color case

C A string listing all cases

D An integer count of cases

allCases returns a collection (array) of all enum cases.

Which of these is a valid way to loop through all cases of a CaseIterable enum Direction?

A for dir in Direction.cases { print(dir) }

B for dir in Direction { print(dir) }

C for dir in Direction.allCases { print(dir) }

D for dir in Direction.iterate() { print(dir) }

You use allCases property to get all cases for looping.

If you add a new case to a CaseIterable enum, what happens to allCases?

A It excludes the new case

B You must update <code>allCases</code> manually

C It breaks the code

D It automatically includes the new case

allCases automatically updates to include all enum cases.

Can enums with associated values conform to CaseIterable?

A Yes, all enums can conform

B No, only enums without associated values can conform

C Only if associated values are Int

D Only if associated values are String

Enums with associated values cannot automatically conform to CaseIterable.

Explain how to use CaseIterable to loop through all cases of an enum in Swift.

Think about how you get all cases and then loop over them.

What are the benefits of making an enum conform to CaseIterable?

Consider how it helps when you want to do something with every case.