I'm trying to get the first letter of a string and store it in another variable which is a string.

So far I have

func getFirstChar(deckName : String) -> String {
    return String(deckName.first)
}

From what I understand from googling this should work, but it doesn't compile with the error

No exact matches in call to initializer

CodePudding user response：

As Joan says, String.first returns an Optional. I'm always leery about using force-unwrapping since it crashes if the thing you are unwrapping is nil, so I would advise against the suggestion of using it to return a non optional string.

I'd suggest a variation on Joan's answer instead:

func getFirstChar(_ deckName : String) -> String {
    return String(deckName.first ?? Character(""))
}

Or

func getFirstChar(_ deckName : String) -> String {
    return deckName.first.map {String($0)} ?? ""
}

Either of those versions will return an empty string if first returns nil (a reasonable return value.)

A third choice is to return an Optional string:

func getFirstChar(_ deckName : String) -> String? {
    return deckName.first.map {String($0)}
}

CodePudding user response：

The problem is that first produces an optional. If you are sure that the deck name won't be nil then use this:

func getFirstChar(_ deckName : String) -> String {
        return String(deckName.first!)
    
}