'subscript' is unavailable: cannot subscript String with an Int, see the documentation comment for discussion of Swift 4?

Question

Swift

there is a string str = "asdlkmaskdnasljkvakjsndfasdf"

for i in 2..<str.count {
      print(str[i])
}

I get the error "'subscript' is unavailable: cannot subscript String with an Int, see the documentation comment for discussion"
What's the problem? What am I doing forbidden?

Answer 1

String(Array(stringToIndex)[index])