How to loop over non-nil items in an array
Swift version: 5.1
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.
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