[Swift 3.0]swift中NSRange与Range

最近在使用NSRange获取字符串的部分字符串时,遇到一个编译报错:

Cannot convert value of type 'NSRange' (aka '_NSRange') to expected argument type 'Range<String.Index>' (aka 'Range<String.CharacterView.Index>')

我的代码是这样的:

       let str = "swift"
        var range = NSRange()
        range.location = 0
        range.length = 2
        
        var rString = str.substring(with: range)

这里只需要将String类型转换为NSString类型即可,即将代码修改如下:

      let str = "swift"
        
        var range = NSRange()
        range.location = 0
        range.length = 2
        
        let ocStr = str as NSString
        
        let rString = ocStr.substring(with: range)
        
        print(rString)