Swift check for nil in optional array

Question

I have an Optional array and need to check a member for nil. Unfortunately that doesn't work like I have expected it to do. It seems like I have to unwrap it however at runtime I don't know whether the value in question is a String, an Int, another array etc. so casting doesn't help (I think)

var nilString: String? = nil

let arr = [1, nilString] as [Any]?

print(nilString)
print(arr?[1])

if (arr?[1] == nil) {
    print("is nil") // doesn't work
}

if case Optional<Any>.none = arr?[1] {
    print("nil")     //would expect this one 
} else {             //but
    print("not nil") //<-- gets printed
}

Alternative ideas on the structure are also welcomed.

You just need to change your array type to let arr: [Any?] = [1, nilString]. You have declared your array type as optional instead of declaring its elements. — Leo Dabus
– Leo Dabus, Commented Feb 15, 2020 at 20:30
Can you share why you think you need to use an array of Any? This seems like a code smell and there is possibly a much better way to deal with the problem than using an array of Any? — Fogmeister
– Fogmeister, Commented Feb 15, 2020 at 20:32
@LeoDabus moving the question mark in the brackets works for me. I've edited the question so your answer would fit. Write it and I will mark as correct, thank you — user2875404
– user2875404, Commented Feb 15, 2020 at 20:39
@Fogmeister bad code. It's literally that, at the moment during prototyping there are a lot of different types and nested types to take care of as the model isn't done yet — user2875404
– user2875404, Commented Feb 15, 2020 at 20:41

Leo Dabus · Accepted Answer · 2020-02-15 20:43:07Z

1

Your problem there is that you have declared your Array type as optional instead of declaring its elements. You just need to change your array declaration to[Any?]. Note that the use of Any it is not useful in most situations. I've been coding in Swift for more than 5 years and I've never needed to declare an element type as Any.

answered Feb 15, 2020 at 20:43

Leo Dabus

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