Swift 4.2, String firstIndex() function error in Xcode playground

Question

I was reading \"The Swift Programming Language Swift 4.2\" and in \"Strings and Characters\" chapter under \"Substrings\" section, the following code is given as an example:

Answer 1

You can try index(of

let index = greeting.index(of: ",") ?? greeting.endIndex

as firstIndex exists in Xcode 10 beta Doc