Completed vectors, sets, maps, functions

src/koans/04_vectors.clj

@@ -3,31 +3,31 @@
 
 (meditations
   "You can use vectors in clojure as array-like structures"
-  (= __ (count [42]))
+  (= 1 (count [42]))
 
   "You can create a vector from a list"
-  (= __ (vec '(1)))
+  (= [1] (vec '(1)))
 
   "Or from some elements"
-  (= __ (vector nil nil))
+  (= [nil, nil] (vector nil nil))
 
   "But you can populate it with any number of elements at once"
-  (= [1 __] (vec '(1 2)))
+  (= [1, 2] (vec '(1 2)))
 
   "Conjoining to a vector is different than to a list"
-  (= __ (conj [111 222] 333))
+  (= [111, 222, 333] (conj [111 222] 333))
 
   "You can get the first element of a vector like so"
-  (= __ (first [:peanut :butter :and :jelly]))
+  (= :peanut (first [:peanut :butter :and :jelly]))
 
   "And the last in a similar fashion"
-  (= __ (last [:peanut :butter :and :jelly]))
+  (= :jelly (last [:peanut :butter :and :jelly]))
 
   "Or any index if you wish"
-  (= __ (nth [:peanut :butter :and :jelly] 3))
+  (= :jelly (nth [:peanut :butter :and :jelly] 3))
 
   "You can also slice a vector"
-  (= __ (subvec [:peanut :butter :and :jelly] 1 3))
+  (= [:butter, :and] (subvec [:peanut :butter :and :jelly] 1 3))
 
   "Equality with collections is in terms of values"
-  (= (list 1 2 3) (vector 1 2 __)))
+  (= (list 1 2 3) (vector 1 2 3)))

src/koans/05_sets.clj

@@ -4,19 +4,19 @@
 
 (meditations
   "You can create a set by converting another collection"
-  (= #{3} (set __))
+  (= #{3} (set #{3}))
 
   "Counting them is like counting other collections"
-  (= __ (count #{1 2 3}))
+  (= 3 (count #{1 2 3}))
 
   "Remember that a set is a *mathematical* set"
-  (= __ (set '(1 1 2 2 3 3 4 4 5 5)))
+  (= #{1 2 3 4 5} (set '(1 1 2 2 3 3 4 4 5 5)))
 
   "You can ask clojure for the union of two sets"
-  (= __ (set/union #{1 2 3 4} #{2 3 5}))
+  (= #{1 2 3 4 5} (set/union #{1 2 3 4} #{2 3 5}))
 
   "And also the intersection"
-  (= __ (set/intersection #{1 2 3 4} #{2 3 5}))
+  (= #{2, 3} (set/intersection #{1 2 3 4} #{2 3 5}))
 
   "But don't forget about the difference"
-  (= __ (set/difference #{1 2 3 4 5} #{2 3 5})))
+  (= #{1 4} (set/difference #{1 2 3 4 5} #{2 3 5})))

src/koans/06_maps.clj

@@ -3,48 +3,48 @@
 
 (meditations
   "Don't get lost when creating a map"
-  (= {:a 1 :b 2} (hash-map :a 1 __ __))
+  (= {:a 1 :b 2} (hash-map :a 1 :b 2))
 
   "A value must be supplied for each key"
-  (= {:a 1} (hash-map :a __))
+  (= {:a 1} (hash-map :a 1))
 
   "The size is the number of entries"
-  (= __ (count {:a 1 :b 2}))
+  (= 2 (count {:a 1 :b 2}))
 
   "You can look up the value for a given key"
-  (= __ (get {:a 1 :b 2} :b))
+  (= 2 (get {:a 1 :b 2} :b))
 
   "Maps can be used as functions to do lookups"
-  (= __ ({:a 1 :b 2} :a))
+  (= 1 ({:a 1 :b 2} :a))
 
   "And so can keywords"
-  (= __ (:a {:a 1 :b 2}))
+  (= 1 (:a {:a 1 :b 2}))
 
   "But map keys need not be keywords"
-  (= __ ({2010 "Vancouver" 2014 "Sochi" 2018 "PyeongChang"} 2014))
+  (= "Sochi" ({2010 "Vancouver" 2014 "Sochi" 2018 "PyeongChang"} 2014))
 
   "You may not be able to find an entry for a key"
-  (= __ (get {:a 1 :b 2} :c))
+  (= nil (get {:a 1 :b 2} :c))
 
   "But you can provide your own default"
-  (= __ (get {:a 1 :b 2} :c :key-not-found))
+  (= :key-not-found (get {:a 1 :b 2} :c :key-not-found))
 
   "You can find out if a key is present"
-  (= __ (contains? {:a nil :b nil} :b))
+  (= true (contains? {:a nil :b nil} :b))
 
   "Or if it is missing"
-  (= __ (contains? {:a nil :b nil} :c))
+  (= false (contains? {:a nil :b nil} :c))
 
   "Maps are immutable, but you can create a new and improved version"
-  (= {1 "January" 2 __} (assoc {1 "January"} 2 "February"))
+  (= {1 "January" 2 "February"} (assoc {1 "January"} 2 "February"))
 
   "You can also create a new version with an entry removed"
-  (= {__ __} (dissoc {1 "January" 2 "February"} 2))
+  (= {1 "January"} (dissoc {1 "January" 2 "February"} 2))
 
   "Often you will need to get the keys, but the order is undependable"
-  (= (list __ __ __)
+  (= (list 2010 2014 2018)
      (sort (keys { 2014 "Sochi" 2018 "PyeongChang" 2010 "Vancouver"})))
 
   "You can get the values in a similar way"
-  (= (list __ __ __)
+  (= (list "PyeongChang" "Sochi" "Vancouver")
      (sort (vals {2010 "Vancouver" 2014 "Sochi" 2018 "PyeongChang"}))))

src/koans/07_functions.clj

@@ -8,33 +8,33 @@
 
 (meditations
   "Calling a function is like giving it a hug with parentheses"
-  (= __ (square 9))
+  (= 81 (square 9))
 
   "Functions are usually defined before they are used"
-  (= __ (multiply-by-ten 2))
+  (= 20 (multiply-by-ten 2))
 
   "But they can also be defined inline"
-  (= __ ((fn [n] (* 5 n)) 2))
+  (= 10 ((fn [n] (* 5 n)) 2))
 
   "Or using an even shorter syntax"
-  (= __ (#(* 15 %) 4))
+  (= 60 (#(* 15 %) 4))
 
   "Even anonymous functions may take multiple arguments"
-  (= __ (#(+ %1 %2 %3) 4 5 6))
+  (= 15 (#(+ %1 %2 %3) 4 5 6))
 
   "Arguments can also be skipped"
-  (= __ (#(* 15 %2) 1 2))
+  (= 30 (#(* 15 %2) 1 2))
 
   "One function can beget another"
-  (= 9 (((fn [] ___)) 4 5))
+  (= 9 ((#(fn [a b] (+ a b))) 4 5))
 
   "Functions can also take other functions as input"
   (= 20 ((fn [f] (f 4 5))
-           ___))
+           *))
 
   "Higher-order functions take function arguments"
-  (= 25 (___
+  (= 25 ((fn [aFun] (aFun 5))
           (fn [n] (* n n))))
 
   "But they are often better written using the names of functions"
-  (= 25 (___ square)))
+  (= 25 ((fn [squre] (squre 5)) square)))