Separating CamelCase string into space-separated words in Swift

extension String {
    func camelCaseToWords() -> String {
        return unicodeScalars.dropFirst().reduce(String(prefix(1))) {
            return CharacterSet.uppercaseLetters.contains($1)
                ? $0 + " " + String($1)
                : $0 + String($1)
        }
    }
}
print("ÄnotherCamelCaps".camelCaseToWords()) // Änother Camel Caps

May be helpful for someone :)

a better full swifty solution... based on AmitaiB answer

extension String {
    func titlecased() -> String {
        return self.replacingOccurrences(of: "([A-Z])", with: " $1", options: .regularExpression, range: self.range(of: self))
            .trimmingCharacters(in: .whitespacesAndNewlines)
            .capitalized
    }
}

One Line Solution

I concur with @aircraft, regular expressions can solve this problem in one LOC!

// Swift 5 (and probably 4?)
extension String {
    func titleCase() -> String {
        return self
            .replacingOccurrences(of: "([A-Z])",
                                  with: " $1",
                                  options: .regularExpression,
                                  range: range(of: self))
            .trimmingCharacters(in: .whitespacesAndNewlines)
            .capitalized // If input is in llamaCase
    }
}

Props to this JS answer.

P.S. I have a gist for snake_case → CamelCase here.

P.P.S. I updated this for New Swift (currently 5.1), then saw @busta's answer, and swapped out my startIndex..<endIndex for his range(of: self). Credit where it's due y'all!