Enum methods and computed properties in Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an enum method in Swift?

An enum method is a function defined inside an enum that can perform actions or return values related to the enum cases. It helps organize behavior specific to the enum.

beginner

What is a computed property in a Swift enum?

A computed property calculates and returns a value each time it is accessed, instead of storing a value. In enums, it can provide extra information based on the current case.

intermediate

How do you define a computed property inside a Swift enum?

You define it like a variable with the keyword var and provide a get block or just return a value directly without storing it.

intermediate

Can enum methods in Swift modify the enum's cases?

No, enum methods cannot change the enum's cases because enums are value types and their cases are fixed. Methods can return new values or perform calculations but not alter the case itself.

beginner

Give an example of a computed property in a Swift enum that returns a description string.

Example:<br>

enum Direction {
  case north, south, east, west
  var description: String {
    switch self {
    case .north: return "Up"
    case .south: return "Down"
    case .east: return "Right"
    case .west: return "Left"
    }
  }
}

What keyword is used to define a computed property in a Swift enum?

A var

B let

C func

D enum

Computed properties are defined using the var keyword because they behave like variables that compute their value.

Can enum methods in Swift change the enum case itself?

A Only for raw value enums

B Yes, always

C Only if marked mutating

D No, enum cases are fixed

Enum cases are fixed and cannot be changed by methods. Methods can return new values but cannot modify the enum case.

Which of the following is a valid use of a computed property in an enum?

A Calculating a value based on the current case

B Changing the enum case

C Storing a value permanently

D Defining a new enum case

Computed properties calculate and return values dynamically based on the enum's current case.

How do you access a computed property in a Swift enum?

A By using square brackets

B By calling it like a function with parentheses

C By using dot notation without parentheses

D By importing a special library

Computed properties are accessed like variables using dot notation without parentheses.

What is the purpose of adding methods inside a Swift enum?

A To store extra data permanently

B To add behavior related to enum cases

C To change the enum's raw values

D To create new enum cases dynamically

Methods inside enums help organize behavior and actions related to the enum cases.

Explain how computed properties work inside Swift enums and give an example.

Think about a variable that calculates its value each time you ask for it.

Describe the role of methods inside Swift enums and why they are useful.

Consider how you might add actions related to each enum case.