complete structured data exercises

src/structured_data.clj

@@ -1,114 +1,137 @@
 (ns structured-data)
 
 (defn do-a-thing [x]
-  :-)
+  (let [xx (+ x x)]
+    (Math/pow xx xx)))
 
 (defn spiff [v]
-  :-)
+  (+ (first v) (get v 2)))
 
 (defn cutify [v]
-  :-)
+  (conj v "<3"))
 
-(defn spiff-destructuring [v]
-  :-)
+(defn spiff-destructuring [[x _ z]]
+  (+ x z))
 
 (defn point [x y]
   [x y])
 
 (defn rectangle [bottom-left top-right]
   [bottom-left top-right])
 
-(defn width [rectangle]
-  :-)
+(defn width [[[x0 _] [x1 _]]]
+  (- x1 x0))
 
-(defn height [rectangle]
-  :-)
+(defn height [[[_ y0] [_ y1]]]
+  (- y1 y0))
 
 (defn square? [rectangle]
-  :-)
+  (= (height rectangle) (width rectangle)))
 
 (defn area [rectangle]
-  :-)
+  (* (height rectangle) (width rectangle)))
 
-(defn contains-point? [rectangle point]
-  :-)
+(defn contains-point? [[[x0 y0] [x1 y1]] [px py]]
+  (and (<= x0 px x1) (<= y0 py y1)))
 
-(defn contains-rectangle? [outer inner]
-  :-)
+(defn contains-rectangle? [outer  [[inx0 iny0] [inx1 iny1]]]
+  (and (contains-point? outer [inx0 iny0]) 
+       (contains-point? outer [inx1 iny1])))
 
 (defn title-length [book]
-  :-)
+  (count (:title book)))
 
 (defn author-count [book]
-  :-)
+  (count (:authors book)))
 
 (defn multiple-authors? [book]
-  :-)
+  (> (author-count book) 1))
 
-(defn add-author [book new-author]
-  :-)
+(defn add-author [book new-author] 
+  (assoc book 
+         :authors 
+         (conj (:authors book) new-author)))
 
 (defn alive? [author]
-  :-)
+  (not (contains? author :death-year)))
 
 (defn element-lengths [collection]
-  :-)
+  (map count collection))
 
 (defn second-elements [collection]
-  :-)
+  (map second collection))
 
 (defn titles [books]
-  :-)
+  (map :title books))
 
 (defn monotonic? [a-seq]
-  :-)
+  (or (apply <= a-seq) 
+      (apply >= a-seq)))
 
 (defn stars [n]
-  :-)
+  (apply str (repeat n "*")))
 
 (defn toggle [a-set elem]
-  :-)
+  (if (contains? a-set elem)
+    (disj a-set elem)
+    (conj a-set elem)))
 
 (defn contains-duplicates? [a-seq]
-  :-)
+  (not= (count a-seq) 
+        (count (set a-seq))))
 
 (defn old-book->new-book [book]
-  :-)
+  (assoc book
+         :authors
+         (set (:authors book))))
 
 (defn has-author? [book author]
-  :-)
+  (contains? (:authors book) author))
 
 (defn authors [books]
-  :-)
+  (apply clojure.set/union (map :authors books)))
 
 (defn all-author-names [books]
-  :-)
+  (set (map :name (authors books))))
 
 (defn author->string [author]
-  :-)
+  (let [name (:name author)
+        birth (:birth-year author)
+        death (:death-year author)]
+    (str name 
+         (if birth
+           (str " (" birth " - " (or death "") ")")
+           ""))))
 
 (defn authors->string [authors]
-  :-)
+  (apply str (interpose ", " (map author->string authors))))
 
 (defn book->string [book]
-  :-)
+  (str (:title book) 
+       ", written by " 
+       (authors->string (:authors book))))
 
 (defn books->string [books]
-  :-)
+  (if (empty? books)
+    "No books."
+    (let [n (count books)
+          header (str n " " (if (= n 1) "book." "books."))
+          bodies (apply str (interpose ". " (map book->string books)))]
+      (str header " " bodies "."))))
 
 (defn books-by-author [author books]
-  :-)
+  (filter #(has-author? % author) books))
 
 (defn author-by-name [name authors]
-  :-)
+  (first (filter #(= name (:name %)) authors)))
 
 (defn living-authors [authors]
-  :-)
+  (filter alive? authors))
 
 (defn has-a-living-author? [book]
-  :-)
+  (not (empty? (filter alive? (:authors book)))))
 
 (defn books-by-living-authors [books]
-  :-)
+  (filter has-a-living-author? books))
 
 ; %________%