Swift 3 中的字符串和索引

Question

这是我的代码的一部分：

let separator = anyWord.indexOf("-")!
if (separator >= 0) {
let res = anyWord[anyWord.characters.index(after: separator)..<anyWord.endIndex] //get an error
//some code
}

我在 'let res' 部分出错 - 类型 'String!' 没有下标成员

如果我这样做：

let separator = anyWord.indexOf("-")!
let subStartIndex = anyWord.characters.index(after: separator)

String 的扩展：

extension String {
    public func indexOf(_ char: Character) -> Int! {
        if let idx = self.characters.index(of: char) {
            return self.characters.distance(from: self.startIndex, to: idx)
        }
        return Const.INVALID_VALUE
    }

我收到错误：

String may not be indexed with 'Int", it has variable size elements

Answer 1

将其转换为字符串

let test: String
test = "Test-Word"
if let separatorWord = anyWord.range(of: "-") 
{
let word = anyWord.substring(from: anyWord.index(after:   
separatorWord.lowerBound))
print(word)
}

Answer 2

你想得太复杂了，在 Swift 3 使用 range(of 和 upperBound

很容易

let anyWord = "asdghf-fkgjh"
if let separator = anyWord.range(of:"-") {
   let res = anyWord.substring(from: separator.upperBound)
   //some code
}

Answer 3

我喜欢 'pure' swift 解决方案（不需要基础）

let anyWord = "asdghf-fkgjh-blablabla--bla"
anyWord.characters.split(separator: "-").forEach { print( String([=10=])) }

它打印

asdghf
fkgjh
blablabla
bla

Swift 3 中的字符串和索引

String and index in Swift 3

nsstring

ios

swift

swift3