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iOS Swift Functions and Optionals Parameters and Tuples Tuples

Posted by Jonathan Shula
Jonathan Shula
1,993 Points

what is the answer to tuples challenge objective 1? i am getting an error: and I don't know how to resolve the problem

swift_lint.swift:11:12: error: '(String, String) -> $T3' is not identical to 'String' return greeting(greeting,language)

I don't know what this error means.

In my playground it states: "Cannot invoke 'greeting' with n argument list of '(String,String)' But because I am trying to return two different strings "language,greeting" I don't know how to have them register as a tuple.

tuples.swift 
func greeting(person: String) -> (String,String) {
    let language = "English"
    let greeting = "Hello \(person)"

    return greeting(greeting,language)
}

1 Answer

Martin Wildfeuer
PLUS
Martin Wildfeuer
Courses Plus Student 11,071 Points
Martin Wildfeuer
Martin Wildfeuer
Courses Plus Student 11,071 Points 
return greeting(greeting,language)

The problem here is the return statement. This way, you are returning the greeting function itself, but greeting expects a single String as a parameter. Moreover it expects two Strings to be returned. Having said that, the function is is not what you want to return, but the greeting and the language string. Therefore, the return statement should read:

return (greeting,language) // Now you are returning a tuple

Another thing worth mentioning is your returned type -> (String, String) lets you access the tuple values like this 

let test = greeting("Martin")
test.0 // Access first variable "Hello Martin"
test.1 // Access second variable "English"

This works, but it is not very descriptive and might be a bit hard to read later on. By returning a named type -> (greeting: String, language: String), you can access the values like this

let test = greeting("Martin")
test.greeting
test.language

So the final could would be something like this

func greeting(person: String) -> (greeting: String, language: String) {
    let language = "English"
    let greeting = "Hello \(person)"
    return (greeting,language)
}

Hope that helps!