rendezvous with cassidoo: 22.09.18

calculate_gpa.clj

(ns calculate-gpa
  (:require [clojure.test :refer [deftest is]]))

(def grade->points                                                                               
  {:A  4                                                                                         
   :A- 3.7                                                                                       
   :B+ 3.3                                                                                       
   :B  3                                                                                         
   :B- 2.7                                                                                       
   :C+ 2.3                                                                                       
   :C  2                                                                                         
   :C- 1.7                                                                                       
   :D+ 1.3                                                                                       
   :D  1                                                                                         
   :D- 0.7                                                                                       
   :F  0})                                                                                       
                                                                                                 
(defn calculate-gpa [grades]                                                                     
  (let [raw-gpa (/ (reduce + (map grade->points grades))                                         
                   (count grades))]                                                              
    (if (double? raw-gpa)                                                                        
      (parse-double (format "%.1f" raw-gpa))                                                     
      raw-gpa)))                                                                                 
                                                                                                 
(deftest calculate-gpa-test                                                                      
  (is (= 4   (calculate-gpa [:A])))                                                              
  (is (= 0   (calculate-gpa [:F :F :F])))                                                        
  (is (= 3.3 (calculate-gpa [:A :A- :B+ :B :B-])))                                               
  (is (= 3.3 (calculate-gpa [:A :B+ :C- :A]))))