Previous Swift 2.0, the option .character for String's type, was obtained using advance and startIndex (pretty much a pain in the butt, so make it an extension and you could have the characters :P )
var kString = "My string"
var countString = count(kString)
for i in 0...countString - 1 {
let index = advance(kString.startIndex, i)
print("INSIDE FOR \(kString[index])")
self.labelAmount.text?.append(kString[index])
}