Merge branch 'Matt-Practice' of https://github.com/matthewDavidson1997/clojure-koans into Matt-Practice

src/koans/18_quote.clj

@@ -4,22 +4,22 @@
 
 (meditations
   "Wrap a quote around a list to suppress evaluation"
-  (= (quote '(1 2 3 4 5)) '(1 2 3 4 5))
+  (= (quote (1 2 3 4 5)) '(1 2 3 4 5))
 
   "There is a shortcut too!"
-  (= (quote ) '(1 2 3 4 5))
+  (= (quote (1 2 3 4 5)) '(1 2 3 4 5))
 
   "You can quote symbols as well as lists... without evaluation!"
-  (= __ (let [age 9] (quote age)))
+  (= 'age (let [age 9] (quote age)))
 
   "You can use a literal list as a data collection without having Clojure try to call a function"
-  (= (cons 1 (__ (2 3))) (list 1 2 3) (cons 1 [2 3]))
+  (= (cons 1 (quote (2 3))) (list 1 2 3) (cons 1 [2 3]))
 
   "The quote affects all of its arguments, not just the top level"
-  (= (list 1 __) '(1 (+ 2 3)))
+  (= (list 1 '(+ 2 3)) '(1 (+ 2 3)))
 
   "Syntax-quote (`) acts similarly to the normal quote"
-  (= (list __ __ __) `(1 2 3) '(1 2 3))
+  (= (list 1 2 3) `(1 2 3) '(1 2 3))
 
   "Unquote (~) within a syntax-quoted expression lets you mark specific expressions as requiring evaluation"
-  (= (list __ __) `(1 ~(+ 2 3)) '(1 5)))
+  (= (list 1 5) `(1 ~(+ 2 3)) '(1 5)))

src/koans/21_partition.clj

@@ -3,19 +3,19 @@
 
 (meditations
   "To split a collection you can use the partition function"
-  (= '((0 1) (2 3)) (__ 2 (range 4)))
+  (= '((0 1) (2 3)) (partition 2 (range 4)))
 
   "But watch out if there are not enough elements to form n sequences"
-  (= '(__) (partition 3 [:a :b :c :d :e]))
+  (= '([:a :b :c]) (partition 3 [:a :b :c :d :e]))
 
   "You can use partition-all to include any leftovers too"
-  (= __ (partition-all 3 (range 5)))
+  (= '((0 1 2) (3 4)) (partition-all 3 (range 5)))
 
   "If you need to, you can start each sequence with an offset"
-  (= '((0 1 2) (5 6 7) (10 11 12)) (partition 3 __ (range 13)))
+  (= '((0 1 2) (5 6 7) (10 11 12)) (partition 3 5 (range 13)))
 
   "Consider padding the last sequence with some default values..."
-  (= '((0 1 2) (3 4 5) (6 :hello)) (partition 3 3 [__] (range 7)))
+  (= '((0 1 2) (3 4 5) (6 :hello)) (partition 3 3 [:hello] (range 7)))
 
   "... but notice that they will only pad up to the given sequence length"
-  (= '((0 1 2) (3 4 5) __) (partition 3 3 [:these :are "my" "words"] (range 7))))
+  (= '((0 1 2) (3 4 5) (6 :these :are)) (partition 3 3 [:these :are "my" "words"] (range 7))))

src/koans/22_group_by.clj

@@ -2,12 +2,12 @@
   (:require [koan-engine.core :refer :all]))
 
 (defn get-odds-and-evens [coll]
-  (let [{odds true evens false} (group-by __ coll)]
+  (let [{odds true evens false} (group-by odd? coll)]
     [odds evens]))
 
 (meditations
   "To categorize a collection by some function, use group-by."
-  (= __ (group-by count ["hello" "world" "foo" "bar"]))
+  (= {3 ["foo" "bar"] 5 ["hello" "world"]} (group-by count ["hello" "world" "foo" "bar"]))
 
   "You can simulate filter + remove in one pass"
   (= (get-odds-and-evens [1 2 3 4 5])
@@ -15,7 +15,7 @@
      [[1 3 5] [2 4]])
 
   "You can also group by a primary key"
-  (= __
+  (= {1 [{:id 1 :name "Bob"} {:id 1 :last-name "Smith"}] 2 [{:id 2 :name "Jennifer"}]}
      (group-by :id [{:id 1 :name "Bob"}
                     {:id 2 :name "Jennifer"}
                     {:id 1 :last-name "Smith"} ]))
@@ -23,13 +23,13 @@
   "But be careful when you group by a non-required key"
   (= {"Bob" [{:name "Bob" :id 1}]
       "Jennifer" [{:name "Jennifer" :id 2}]
-      __ [{:last-name "Smith" :id 1}]}
+     nil [{:last-name "Smith" :id 1}]}
    (group-by :name [{:id 1 :name "Bob"}
                     {:id 2 :name "Jennifer"}
                     {:id 1 :last-name "Smith"}]))
 
   "The true power of group-by comes with custom functions"
-  (= __
+  (= {:naughty-list [{:name "Jimmy" :bad true} {:name "Joe" :bad true}] :nice-list [{:name "Jane" :bad false}]}
      (group-by #(if (:bad %) :naughty-list :nice-list)
                [{:name "Jimmy" :bad true}
                 {:name "Jane" :bad false}

src/koans/24_macros.clj

@@ -9,8 +9,8 @@
 
 (defmacro infix-concise [form]
   `(~(second form) ; Note the syntax-quote (`) and unquote (~) characters!
-    __
-    __))
+    ~(first form)
+    ~(nth form 2)))
 
 (defmacro recursive-infix [form]
   (cond (not (seq? form))
@@ -27,13 +27,13 @@
 
 (meditations
   "Macros are like functions created at compile time"
-  (= __ (hello "Macros!"))
+  (= "Hello, Macros!" (hello "Macros!"))
 
   "I can haz infix?"
-  (= __ (infix (9 + 1)))
+  (= 10 (infix (9 + 1)))
 
   "Remember, these are nothing but code transformations"
-  (= __ (macroexpand '(infix (9 + 1))))
+  (= '(+ 9 1) (macroexpand '(infix (9 + 1))))
 
   "You can do better than that - hand crafting FTW!"
   (= '(* 10 2) (macroexpand '(infix-concise (10 * 2))))