Swift Optionals - How to Unwrap (real examples)

A common iOS Dev interview question is to explain Optionals and how to unwrap them. In this Swift optionals tutorial I'll explain if let, guard statements, optional chaining, and force unwrapping, and nil coalescing.

This tutorial was created using Xcode 14 and iOS 16.

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Timestamps:
0:00 - What are Optionals
0:59 - Unwrapping - if let
2:57 - Unwrapping - guard let
5:37 - Unwrapping - nil coalescing
7:15 - Force Unwrapping
8:37 - Optional Chaining
9:58 - Real Example - if let
11:09 - Real Example - guard let
11:44 - Real Example - nil coalescing
12:15 - Real Example - force unwrap

[david-holmes]

Good stuff! I frequently avoid the simple nesting logic issue at 2:30 by combining the tests in the if let (if let age = user.age, age > 40)

[kevyyt]

Been coding for 40 years. Force unwrap is important to me and I use it all the time BC I want to know right when my code logic is invalid to result in an invalid nil. It does me no good to fail silently then later on find out that some variable was nil minutes ago. This is particularly true when designing/debugging. Then you’ll have some confidence that the code is “fully” functioning (does that ever really happen).

[androspuddy]

Wow! This is a tough topic for beginners but your delivery was awesome, hands down! Thank you so much for this !!

[thomasgarayua]

Yo you the man, Sean Allen. Thanks for explaining these things in easy nontechnical terms

[Niram]

i agree with you on the force unwrap example. other example might be the IBOutlets.. they already come with a force unwrap from Apple, because yes, you shold have those components. good video again Sean

[derickito]

In the calendar code I would not use Calendar.current. I recently had to fix a crash related to this. Create a Calendar manually with the Gregorian identifier or you may get unknown behavior.
The issue is that the user may have a non-Gregorian calendar set

[ayurockt]

Thank you for the great video! Helped me a lot :)
The "cache example" looks really interesting.
Maybe you could do a video about caching?

[nahidislam]

there’s stigma against force unwrapping optionals. Don’t be afraid of force unwrapping when you expect a non-nil value at point of accessing the variable. Running if-lets because “you don’t want the app crashing due to an edge case” will bite in future when debugging your code later

if the app crash happens due to unexpected nil that’s a sign you need to fix the code itself; not the variable

[andreifokin]

Thanks a lot! Usefull topic for both beginners and advanced. What about unwrap with compactMap and type casting (as?)

[JasonMitchellAZ]

Great explanations as always, Sean!

[antonignatenko]

'm new to Swift and trying to solve some LeetCode problems in Xcode. I realized that I can't debug in Playgrounds, which makes it hard to see what I'm doing. How can I learn Swift effectively without a debugger? Any advice would be appreciated.
Can I use regular projects as my test ground ?

[waldifebrianda]

@Sean Allen : sir could you create video about restfull API in swift 5.7, thank you

[finnmonstar]

I would love for Rust to be a supported language for Apple development.

[officialspaceefrain]

I’m working with Dates and I see no reason to no force unwrap UNLESS I don’t know what date is coming through.

Make 100% sure you know what date object is coming through and then make it happen.

[jaylensmith]

Force unwrapping is helpful with UIImage I’ve found. As long as the image asset name matches the string value, It has always worked in my case. Of course ?? is always there, but then you’ll be force unwrapping that default UIImage value regardless…

[mgcarland]

Optional map is also very useful when you want to pass the non-nil value to a function, otherwise keep the nil:
let width = Float(widthTextField.text ?? “”).map { } ?? nil