Swift’s Type annotations

They can be inferred

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Let’s take a look.

Difficulty: Beginner | Easy | Normal | Challenging

This article has been developed using Xcode 14.2, and Swift 5.7.2

Prerequisites

None

type annotation

There are times where we would want to explicitly declare the type of a property. Something like this:

var count: Int = 0

The type is optional, and the following is more than acceptable in Swift.

var count = 0

where the type can be inferred as an integer.

So why would we ever want to explicitly declare a type?

I would say generally for clarity. Or to clear up an ambiguity.

When Swift infers the type it might not do quite what we want. Consider the following code

var number = 0 // inferred Int
var numberFloat: Float = 0 // explicit Float

If we want number to be a Float we would need to explicitly define that (as in the numberFloat example).

Type inference may not always be straight forwards, so type annotation can be used alongside various Swift construct including variables…