FizzBuzz without ifs

fizz_buzz.clj

;; First solution

(defn fizz-buzz-or-number
  [x]
  (
   ["FizzBuzz" x x "Fizz" x "Buzz" "Fizz" x x "Fizz" "Buzz" x "Fizz" x x]
   (mod x 15)))

(defn fizz-buzz
  [xs]
  (doseq [x (map fizz-buzz-or-number xs)]
    (println x)))


(comment
  (fizz-buzz (range 1 101))
  (fizz-buzz [1 3 5 10 12 13 15])
  )

;; Alternative solution.
;; I like this better, but it works better for a continuous range of numbers

(defn- make-seq
  "Makes a sequence that returns name at each nth element and nil for others"
  [name nth]
  (cycle (concat (repeat (dec nth) nil) [name])))

(def fizzes (make-seq "Fizz" 3))
(def buzzes (make-seq "Buzz" 5))
(def fizzbuzzes (make-seq "FizzBuzz" 15))

(def first-non-nil #(some identity %&))

;; a lazy seq of FizzBuzzes, Fizzes, Buzzes, and numbers
(def fizz-buzz-seq
  (map first-non-nil fizzbuzzes fizzes buzzes (iterate inc 1)))

(defn fizz-buzz-range
  "Returns FizzBuzz elements from start (inclusive) to end
  (exclusive), where start defaults to 1."
  ([end] (fizz-buzz-range 1 end))
  ([start end]
   {:pre [(< start end)]}
   (->> fizz-buzz-seq
        (drop (dec start))
        (take (- end start)))
   ))

;; The fizz-buzz-range works well for continuous ranges as the original FizzBuzz problem.
;; This function is to satisfy the spec in the newsletter (ie. pass in integers that could
;; be non-continuous)
(defn fizz-buzz-alternative
[xs]
(doseq [x (map #(first (fizz-buzz-range % (inc %))) xs)]
  (println x)))

(comment
  (fizz-buzz-range 101)
  (fizz-buzz-range 100 201)
  (fizz-buzz-alternative [1 3 5 9 10 12 13 15])
)