Raw values for enums in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a raw value in a Swift enum?

A raw value is a constant value of a specific type (like String or Int) that each enum case can have. It lets you assign a fixed value to each case.

beginner

How do you declare an enum with raw values in Swift?

You add a type after the enum name, like enum Direction: String, then assign raw values to each case, e.g., case north = "N".

intermediate

Can raw values be of any type in Swift enums?

No, raw values must be of a literal type like String, Int, or Character. You cannot use complex types like arrays or dictionaries as raw values.

beginner

How do you access the raw value of an enum case?

Use the .rawValue property on the enum case. For example, Direction.north.rawValue returns the raw value assigned to north.

intermediate

How can you create an enum case from a raw value?

Use the initializer EnumType(rawValue: value). It returns an optional enum case matching the raw value or nil if no match is found.

Which of these is a valid raw value type for a Swift enum?

A Array

B String

C Dictionary

D Class

Raw values must be literal types like String, Int, or Character. Arrays, dictionaries, and classes are not allowed.

How do you declare an enum with Int raw values starting from 1?

A enum Number: String { case one = "1", two, three }

B enum Number { case one = 1, two, three }

C enum Number: Int { case one = 1, two, three }

D enum Number: Int { case one, two, three }

You specify the raw value type after the enum name and assign the first case a raw value. The rest auto-increment.

What does Direction(rawValue: "N") return if Direction enum has a case with raw value "N"?

A The enum case matching "N"

B nil

C A string "N"

D An error

The initializer returns the enum case that has the raw value "N" or nil if none matches.

What is the type of Direction.north.rawValue if Direction is declared as enum Direction: String?

A String

B Direction

C Int

D Optional String

The rawValue property returns the raw value type, which is String in this case.

Can you assign different raw value types to different cases in the same enum?

A Only if the enum is generic

B Yes, each case can have its own type

C Only if you use associated values

D No, all cases must have the same raw value type

All enum cases must share the same raw value type declared for the enum.

Explain what raw values are in Swift enums and how to use them.

Think about fixed values assigned to enum cases.

Describe the difference between raw values and associated values in Swift enums.

Consider how each enum case stores data.