Computed properties are a powerful feature in Swift that allow you to define custom getter and setter methods for a property. This enables you to perform custom logic or calculations whenever the property is accessed or updated. Computed properties provide a flexible way to encapsulate logic within a property, without the need to store an actual value.
Let's take a look at an example of a computed property in Swift:
struct Circle {
var radius: Double
var area: Double {
return Double.pi * radius * radius
}
}
let circle = Circle(radius: 5)
print("The area of the circle is \(circle.area)")}
In this example, we have a `Circle` struct with a `radius` property and a computed property `area`. The `area` property calculates the area of the circle based on its radius using the formula for the area of a circle (πr²).
Computed properties are useful when you need to perform calculations, validations, or transformations on a property's value. They are ideal for properties that depend on other properties or external factors, or when you want to add custom behavior to property access.
However, it's important to note that computed properties come with a performance cost, as the getter/setter methods are called whenever the property is accessed or updated. As such, they should be used judiciously and not for properties that require frequent access or updates.
Overall, computed properties are a valuable tool in Swift for creating dynamic and flexible properties that encapsulate custom logic and behavior.