What is a computed property?
Swift version: 5.6
Swift offers us two kinds of property: a stored property is one that saves a value for use later, and a computed property is one that runs some code in order to calculate the value.
As comparison, here’s a Person struct with four stored properties and one computed one. The computed property returns a string based on joining the four stored properties into a sentence.
struct Person {
var name = "Taylor"
var favoriteColor = "red"
var favoriteCity = "Tokyo"
var favoriteFood = "tea"
var greeting: String {
return "Hello, my name is \(name), and I like \(favoriteFood), \(favoriteCity), and the color \(favoriteColor)."
}
}Note: Unlike stored properties, Swift requires you to use an explicit type with your computed properties.
BUILD THE ULTIMATE PORTFOLIO APP Most Swift tutorials help you solve one specific problem, but in my Ultimate Portfolio App series I show you how to get all the best practices into a single app: architecture, testing, performance, accessibility, localization, project organization, and so much more, all while building a SwiftUI app that works on iOS, macOS and watchOS.
Sponsor Hacking with Swift and reach the world's largest Swift community!
Available from iOS 8.0
Similar solutions…
- All SwiftUI property wrappers explained and compared
- How to fix “Cannot assign to property: 'self' is immutable”
- Understanding property wrappers in Swift and SwiftUI
- What is the @GestureState property wrapper?
- What is the @Published property wrapper?
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
