彼得潘的iOS App程式設計入門4
let string = “Hello.World”
let idx = string.characters.index(of: “.”) //傳回5
let myRange = idx!..<string.endIndex
string.substring(with:myRange) //傳回.World
//希望 擷取的字串是 World 而不是 .World
終於有作業可以交了..