官方文档
let snowy = "❄️ Let it snow! ☃️"
let nsrange = NSRange(location: 3, length: 12)
if let range = Range(nsrange, in: snowy) {
print(snowy[range])
}
// Prints "Let it snow!"
String拓展
extension String {
func toRange(_ range: NSRange) -> Range<String.Index>? {
return Range(range,in:self)
}
