swift - Swift 4 不会在 switch 中拾取单引号 ("\'")

Question

我最近下载了 Xcode 测试版并正在使用 swift 4 进行编码。

我创建了一个这样的开关：

func key(cipher: Character) -> Int{
        let someCharacter: Character = cipher
        switch someCharacter {
        case "\'":
            return 27
        case "\"":
            return 28 
        default:
            return -1  //error
        } 
}

我希望能够输入 ' 并得到 27。我该怎么做？

编辑：我还有一个按钮：

@IBAction func encrypt(_ sender: Any) { 
    inputedValues = String(input.text!)!
    let index = inputedValues.index(inputedValues.startIndex, offsetBy: 1)
        var number = key(cipher: inputedValues[index]) }

Answer 1

这在 Playground 中使用 Xcode 9 Beta 和 Swift 4 有效。尝试这个：

func key(_ cipher: Character) -> Int{
    let someCharacter: Character = cipher
    switch someCharacter {
    case "'":
        return 27
    default:
        return -1  //error
    }
}

let input = "1'"
let index = input.characters.index(input.startIndex, offsetBy: 1)
let cipher = input[index] // Returns second character

key(cipher) //Output is 27

Answer 2

部分修复：

func key(cipher: Character) -> Int{
        let someCharacter: Character = cipher
        switch someCharacter {
        case "’": //not "\'" or "'"
            return 27
        case "\"":
            return 28 
        default:
            return -1  //error
        }
}