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iOS

Cory Sovilla
Cory Sovilla
11,087 Points
Posted by Cory Sovilla
Cory Sovilla
11,087 Points

Is it possible to have a Dictionary have a Tuple as a value?

In my code I have a Dictionary that contains a tuple for its value but I am having trouble calling the values inside the tuple.

For example,

var testingCode: [String:(Int,Bool)] = [ "Joe":(41,true),"Bob":(36,false)]

How would I go about getting the values of 41 and true from Joe?

I get an Error when I type

testingCode["Joe"].0 or testingCode["Joe"].1 and the error tells me to put a !(Optional) as follows:

testingCode["Joe"]!.0 // I dont understand why it wants the !

Is there a way to make it where the ! is not needed?

1 Answer

Martin Wildfeuer
Martin Wildfeuer
Courses Plus Student 11,071 Points

This is intended behavior of a dictionary and has nothing to do with the values being tuples. Getting a value from a dictionary will always return an optional, as it is possible that the key (and therefore the value) do not exist. For example, with this code

let testingCode: [String:(Int,Bool)] = [ "Joe":(41,true),"Bob":(36,false)]
let test = testingCode["Anna"] // using ! here would crash the app

test would be nil, as the key does not exist. In order to handle this scenario correctly, you have to unwrap the optional. Never, I repeat, never force unwrap this with ! as this will crash your app in case the key does not exist. Force unwrapping basically works against Swifts great safety introduced with optionals. Make yourself familiar with the concept of optionals, a good resource are the Apple Docs.

So, here is an example on how to do it

let testingCode: [String:(Int,Bool)] = [ "Joe":(41,true),"Bob":(36,false)]

// Unwrapping
if let test = testingCode["Joe"] {
    print(test.0)
}

// Alternatively, unwrapping with guard
guard let test = testingCode["Joe"] else {
    return
}
print(test.0)

Hope that helps :)