Swift String 相关

1. 截取 String

var str = "（aaa）哈哈"
let index = str.range(of: "）")!
let preStr = str.prefix(upTo: index.upperBound) // “（aaa）”
let sufStr = str.suffix(from: index.upperBound)// “哈哈”

2. 遍历 String

let str = "abcdefghhi"
for cha in str {
    print(cha)
}