swift - 在 Swift 3.0 中循环遍历子字符串

Question

在 Swift 3.0 中循环遍历子字符串的最佳方法是什么？

var start = s.startIndex
var end = s.index(s.endIndex, offsetBy: -10)
   for i in start...end {


   }

以下代码会引发错误:Type ClosedRange<String.Index> (aka ‘ClosedRange<String.CharacterView.Index>’) does not conform to Sequence protocol .

Answer 1

start和end是String.Index的类型，不能在for循环中使用；相反，您可以获得以下范围内的 substring:

var start = s.startIndex
var end = s.index(s.endIndex, offsetBy: -10)
let range = Range(uncheckedBounds: (lower: start, upper: end))
let subString = s.substring(with: range)