FREE TRIAL: Accelerate your app development career with Hacking with Swift+! >>

DAY 14


Null references – literally when a variable has no value – were invented by Tony Hoare way back in 1965. When asked about it in retrospect, he said “I call it my billion-dollar mistake” because they lead to so many problems.

This is the last day that you’ll be learning the fundamentals of Swift, and it’s devoted exclusively to Swift’s solution to null references, known as optionals. These are a really important language feature, but they can hurt your brain a little – don’t feel bad if you need to repeat some tutorials a few times.

In essence, an optional is trying to answer the question “what if our variable doesn’t have any sort of value at all?” Swift wants to make sure all our programs are as safe as possible, so it has some very specific – and very important! – techniques for handling this eventuality.

Today you have five tutorials to work through, where you’ll meet optionals, optional unwrapping, nil coalescing, and more. Once you’ve watched each video and optionally gone through the extra reading, there are short tests to help make sure you’ve understood what was taught.

Tip: Yes, there is optional reading about optionals, but these optionals aren’t empty!

  1. How to handle missing data with optionals
  2. How to unwrap optionals with guard
  3. How to unwrap optionals with nil coalescing
  4. How to handle multiple optionals using optional chaining
  5. How to handle function failure with optionals
  6. Summary: Optionals
  7. Checkpoint 9

Have some questions about optionals?

Hit Send below to start a virtual conversation with me.

Need help? Tweet me @twostraws!


Hacking with Swift is sponsored by Essential Developer

SPONSORED Join a FREE crash course for iOS devs who want to become complete senior developers — from October 18th to 24th. Learn how to apply iOS app architecture patterns through a series of lectures and practical coding sessions.

Learn more

Sponsor Hacking with Swift and reach the world's largest Swift community!

100 Days of SwiftUI

The 100 Days of SwiftUI is a free collection of videos, tutorials, tests, and more to help you learn SwiftUI faster. Click here to learn more, or watch the video below.

Back to 100 Days of SwiftUI

Unknown user

You are not logged in

Log in or create account

Link copied to your pasteboard.