WWDC24 SALE: Save 50% on all my Swift books and bundles! >>

Unwrapping optionals

Optional strings might contain a string like “Hello” or they might be nil – nothing at all.

Consider this optional string:

var name: String? = nil

What happens if we use name.count? A real string has a count property that stores how many letters it has, but this is nil – it’s empty memory, not a string, so it doesn’t have a count.

Because of this, trying to read name.count is unsafe and Swift won’t allow it. Instead, we must look inside the optional and see what’s there – a process known as unwrapping.

A common way of unwrapping optionals is with if let syntax, which unwraps with a condition. If there was a value inside the optional then you can use it, but if there wasn’t the condition fails.

For example:

if let unwrapped = name {
    print("\(unwrapped.count) letters")
} else {
    print("Missing name.")
}

If name holds a string, it will be put inside unwrapped as a regular String and we can read its count property inside the condition. Alternatively, if name is empty, the else code will be run.

Save 50% in my WWDC sale.

SAVE 50% To celebrate WWDC24, all our books and bundles are half price, so you can take your Swift knowledge further without spending big! Get the Swift Power Pack to build your iOS career faster, get the Swift Platform Pack to builds apps for macOS, watchOS, and beyond, or get the Swift Plus Pack to learn advanced design patterns, testing skills, and more.

Save 50% on all our books and bundles!

BUY OUR BOOKS
Buy Pro Swift Buy Pro SwiftUI Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let us know!

Average rating: 4.4/5

 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.