I'm converting my Swift2.3 code to Swift3, and got an error at the line where I used advancedBy. XCode showing me a replacing code that using offsetBy, but I still don't understand.
func unhideEmaimage(_ imageFile: String) {
let dotLocation = imageFile.characters.index(of: ".")
self.emaImage.texture = SKTexture(imageNamed: imageFile)
if dotLocation != nil {
let filenameInitial = imageFile.startIndex
let filenameLast = dotLocation!.advancedBy(-1)
let filenamePart:String = imageFile[filenameInitial...filenameLast]
}
And, following is the code that XCode showing me how to fix the error. However, I still don't know how to modify.
let filenameLast = "String.CharacterView corresponding to your index".index(dotLocation!, offsetBy: -1)
Please let me know the way to fix this error. Thank you in advance.