Code from my example on https://news.ycombinator.com/item?id=8899387

grime-dice.clj

(ns grime-dice
  (:require
   [clojure.pprint :refer [print-table]]))

(def dice
  {:red [4 4 4 4 4 9]
   :yellow [3 3 3 3 8 8]
   :blue [2 2 2 7 7 7]
   :magenta [1 1 6 6 6 6]
   :olive [0 5 5 5 5 5]})

(defn round
  [x]
  (Double/parseDouble (format "%.3f" x)))

(defn average
  [xs]
  (-> (reduce + xs)
      (/ (count xs))))

(defn exp-sequential
  [arg]
  {:pre [(sequential? arg)]}
  (round (double (average arg))))

(declare exp)

(defn exp-map
  [arg]
  {:pre [(map? arg)]}
  (->> arg
       (map (fn [[k vs]] [k (exp vs)]))
       (into {})))

(defn exp
  [arg]
  (cond (sequential? arg) (exp-sequential arg)
        (map? arg) (exp-map arg)))

(defn order-keys-by
  "Returns map's keys, ordered by applying f to map values."
  [f xs]
  (map first (sort-by second (f xs))))

(defn table
  [dice]
  (print-table (order-keys-by exp dice) [(exp dice)]))