如何使用Swift子串？ios xcode

Question

swift中的子串联感觉非常复杂

我想得到

abc

从

word(abc)

这样做最简单的方法是什么？

我怎样才能修复下面的代码？

let str = "word(abc)"

// get index of (
let start = str.rangeOfString("(")

// get index of ) 
let end = str.rangeOfString(")")  

// substring between ( and )
let substring = str[advance(str.startIndex, start!.startIndex), advance(str.startIndex, end!.startIndex)] 

Answer 1

Xcode 8.2•Swift 3.0.2

let text = "word(abc)"

// substring between ( and )
if let start = text.range(of: "("),
    let end  = text.range(of: ")", range: start.upperBound..<text.endIndex) {
    let substring = text[start.upperBound..<end.lowerBound]    // "abc"
} else {
    print("invalid input")
}