Like regular optionals, implicitly unwrapped optionals might contain a value or they might be nil
. However, unlike regular optionals you don’t need to unwrap them in order to use them: you can use them as if they weren’t optional at all.
Implicitly unwrapped optionals are created by adding an exclamation mark after your type name, like this:
let age: Int! = nil
Because they behave as if they were already unwrapped, you don’t need if let
or guard let
to use implicitly unwrapped optionals. However, if you try to use them and they have no value – if they are nil
– your code crashes.
Implicitly unwrapped optionals exist because sometimes a variable will start life as nil, but will always have a value before you need to use it. Because you know they will have a value by the time you need them, it’s helpful not having to write if let
all the time.
That being said, if you’re able to use regular optionals instead it’s generally a good idea.
SPONSORED Would you describe yourself as knowledgeable, but struggling when you have to come up with your own code? Fernando Olivares has a new book containing iOS rules you can immediately apply to your coding habits to see dramatic improvements, while also teaching applied programming fundamentals seen in refactored code from published apps.
Sponsor Hacking with Swift and reach the world's largest Swift community!
Link copied to your pasteboard.