Getting Clojure

Composing a Solution

You can get a huge amount of programming mileage out of sequences and the panoply of functions that Clojure provides to process them. For example, imagine that you were working on a sales application for your book business and, starting with the books vector we saw earlier, you needed to format a string proclaiming the three top-rated books, something like this:

"Emma // Dracula // Deep Six"

Step one is to find the top three books, by rating. We could start by sorting the books by their rating:

(sort-by :rating books)

That will give us the books from lowest to highest rating, but the other way around is more useful:

(reverse (sort-by :rating books))

Then we can then pull out the three highest-rated books, with take ...