Uppercase Only First Letter of String in Swift IOS

To capitalize only first letter of a string in Swift iOS. Below is the code for both Swift 3 and Swift 4.

Uppercase First Letter in String in Swift 4

extension String {
    func capitalizingFirstLetter() -> String {
      return prefix(1).uppercased() + dropFirst()
    }

    mutating func capitalizeFirstLetter() {
      self = self.capitalizingFirstLetter()
    }
}

Uppercase First Letter in String in Swift 3

extension String {
    func capitalizingFirstLetter() -> String {
        let first = String(characters.prefix(1)).capitalized
        let other = String(characters.dropFirst())
        return first + other
    }

    mutating func capitalizeFirstLetter() {
        self = self.capitalizingFirstLetter()
    }
}