What is wrong with this piece of code for constructing a range that should then serve in a call to
let range = Range<String.Index>(start: 0, end: 3)
Cannot invoke initializer for type 'Range<Index>' with an argument list of type '(start: Int, end: Int)'
You need to reference the startIndex of a specific string, then advance:
let longString = "Supercalifragilistic" let startIndex = longString.startIndex let range = Range(start: startIndex, end: startIndex.advancedBy(3))