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Johann Peters
40,749 PointsSomething's messed up in this challenge!?
Challenge description asks for a firstLetter function. The error message says I need to declare a firstName function! Can anybody help me out?
// Enter your code below
extension String{
func modify(operation: String -> String) -> String{
return operation(self)
}
}
func firstName(String -> String){
return String.characters.prefix(1)
}
3 Answers
pascalac
237 PointsHi Johann,
the function firstName should get a String as a parameter and return a String. You wrote a function that gets a closure as parameter and has no return type.
Something like this should be fine:
// Enter your code below
extension String{
func modify(operation: String -> String) -> String{
return operation(self)
}
}
func firstName(input: String) -> String { // No closure as parameter here, just a normal String and return String
return String(input.characters.prefix(1)) // You need to cast the result of prefix back to String
// return String(input.characters.first!) // Other possible solution
}
I hope I could help. :)
Alistair Cooper
Courses Plus Student 7,020 PointsI tried using characters.first , which didn't work. Does anyone have any ideas why? (I see in xcode that it returns an optional might that have something to do with it?)
extension String {
func modify(s: String -> String) -> String {
return s(self)
}
}
func firstLetter(s: String) -> String {
return s.characters.first
}
pascalac
237 PointsYes it's because .first returns an optional and so it doesn't match with your return type (String? != String). So you need to unwrap it first. If you're 100% sure that there'll be always a value inside you can just say "s.characters.first!". And I think you've to cast this back to String as well but I'm not sure about that. I've added the .first solution to my previous answer :)
Alistair Cooper
Courses Plus Student 7,020 PointsThanks Pascalac! That makes sense. -A