In this example, the code is the promised rewrite of a snippet in Chapter 2, Working with Collections; Accessing collections as iterators.

The traditional range syntax (n .. m) is exclusive, meaning that 0 .. 5 will only include the numbers 0, 1, 2, 3, and 4. This is good for uses cases where you count up to a length of something, but in our case, we want to iterate over the alphabet, including Z [5]. The inclusive range syntax (n ..= m) helps us by including the last element, so that 0 ..= 5 will yield 0, 1, 2, 3, 4, and 5.