How to loop over non-nil items in an array
Swift version: 5.6
Consider an array of items containing some optionals, like this one:
let numbers: [Int?] = [1, nil, 3, nil, 5]If you want to loop over all the items and print them out, you’d write something like this:
for number in numbers {
print(number)
}However, that prints out all items in their current state: optionally wrapped integers for some, nil for others.
With a small change to that loop, you can have Swift unwrap all the optionals then only enter the loop for any that contain a value – any nil items are ignored. This is done using for case let syntax, like this:
for case let number? in numbers {
print(number)
}That will print the numbers 1, 3, and 5.
SPONSORED In-app subscriptions are a pain to implement, hard to test, and full of edge cases. RevenueCat makes it straightforward and reliable so you can get back to building your app. Oh, and it's free if your app makes less than $10k/mo.
Sponsor Hacking with Swift and reach the world's largest Swift community!
Available from iOS – learn more in my book Pro Swift
Similar solutions…
- How to use the forEach method to loop over an array
- Using stride() to loop over a range of numbers
- How to loop through items in an array
- How to detect the user hovering over a view
- How to modify haptic events over time using CHHapticParameterCurve
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
