[1]: https://www.swift.org/blog/utf8-string/

There were many discussions on how to handle strings in the forums too. Remarkably, it is not possible to access "abc"[1] as it has unpredictable performance; instead one has to build the index and making this should make the developer realize the operation is costly. All in all most beginners in Swift hate working with strings because it’s not intuitive at first, but to be fair in almost all languages strings handling is not done properly.