Long day 3

.travis.yml

@@ -1,6 +1,6 @@
 language: clojure
-lein: lein2
-script: lein2 midje :config .midje-grading-config.clj
+lein: lein
+script: lein midje :config .midje-grading-config.clj
 jdk:
   - openjdk7
 notifications:

src/structured_data.clj

@@ -1,16 +1,27 @@
 (ns structured-data)
 
 (defn do-a-thing [x]
-  :-)
+  (let [y (+ x x)]
+    (Math/pow y y)))
+
+; (do-a-thing 1.00)
+; [:foo 42 "bar" (+ 2 3)]
 
 (defn spiff [v]
-  :-)
+  (+ (get v 0) (get v 2)))
+
+; (spiff [1 2 33])
 
 (defn cutify [v]
-  :-)
+  (conj v "<3"))
+
+; (cutify [1 2])
 
 (defn spiff-destructuring [v]
-  :-)
+  (let [[a _ b] v]
+    (+ a b)))
+
+; (spiff-destructuring [1 2 33])
 
 (defn point [x y]
   [x y])
@@ -19,96 +30,300 @@
   [bottom-left top-right])
 
 (defn width [rectangle]
-  :-)
+  (let [[[x0 y0] [x1 y1]] rectangle]
+    (- x1 x0)))
+
+; (width (rectangle [1 1] [5 1]))
+; (width (rectangle [1 1] [1 1]))
+; (width (rectangle [3 1] [10 4]))
 
 (defn height [rectangle]
-  :-)
+  (let [[[x0 y0] [x1 y1]] rectangle]
+    (- y1 y0)))
+
+; (height (rectangle [1 1] [5 1]))
+; (height (rectangle [1 1] [5 5]))
+; (height (rectangle [0 0] [2 3]))
+
 
 (defn square? [rectangle]
-  :-)
+  (= (height rectangle) (width rectangle)))
 
-(defn area [rectangle]
-  :-)
+; (square? (rectangle [1 1] [2 2])) ;=> true
+; (square? (rectangle [1 1] [2 3])) ;=> false
+; (square? (rectangle [1 1] [1 1])) ;=> true
+; (square? (rectangle [3 2] [1 0])) ;=> true
+; (square? (rectangle [3 2] [1 1])) ;=> false
 
-(defn contains-point? [rectangle point]
-  :-)
+
+(defn area [rectangle]
+  (* (height rectangle) (width rectangle)))
+
+; (area (rectangle [1 1] [5 1]))  ;=> 0
+; (area (rectangle [0 0] [1 1]))  ;=> 1
+; (area (rectangle [0 0] [4 3]))  ;=> 12
+; (area (rectangle [3 1] [10 4])) ;=> 21
+
+(defn contains-point?
+  "_"
+  [rectangle point]
+  (let [[[x0 y0] [x1 y1]] rectangle
+        [x y] point]
+    (and (<= x0 x x1)(<= y0 y y1))))
+
+; (contains-point? (rectangle [0 0] [2 2])
+;                 (point 1 1))            ;=> true
+; (contains-point? (rectangle [0 0] [2 2])
+;                 (point 2 1))            ;=> true
+; (contains-point? (rectangle [0 0] [2 2])
+;                 (point -3 1))           ;=> false
+; (contains-point? (rectangle [0 0] [2 2])
+;                 (point 1 3))            ;=> false
+; (contains-point? (rectangle [1 1] [2 2])
+;                 (point 1 1))            ;=> true
+; (contains-point? (rectangle [1 1] [1 1])
+;                 (point 1 1))            ;=> true
 
 (defn contains-rectangle? [outer inner]
-  :-)
+  (let [[bottom-left top-right] inner]
+    (and (contains-point? outer bottom-left) (contains-point? outer top-right))))
+
+; (contains-rectangle? (rectangle [0 0] [3 3])
+;                     (rectangle [1 1] [2 2])) ;=> true
+; (contains-rectangle? (rectangle [0 0] [2 2])
+;                     (rectangle [1 1] [3 3])) ;=> false
+; (contains-rectangle? (rectangle [0 0] [1 1])
+;                     (rectangle [0 0] [1 1])) ;=> true
+; (contains-rectangle? (rectangle [0 0] [1 1])
+;                     (rectangle [1 1] [2 2])) ;=> false
+
+; (def china {:name "China Miéville", :birth-year 1972})
+; (def octavia {:name "Octavia E. Butler"
+;              :birth-year 1947
+;              :death-year 2006})
+; (def friedman {:name "Daniel Friedman" :birth-year 1944})
+; (def felleisen {:name "Matthias Felleisen"})
+
+; (def cities {:title "The City and the City" :authors [china]})
+; (def wild-seed {:title "Wild Seed", :authors [octavia]})
+; (def embassytown {:title "Embassytown", :authors [china]})
+; (def little-schemer {:title "The Little Schemer"
+;                     :authors [friedman, felleisen]})
+
 
 (defn title-length [book]
-  :-)
+  (count (:title book)))
+
+; (title-length cities)         ;=> 21
+; (title-length wild-seed)      ;=> 9
+; (title-length little-schemer) ;=> 18
 
 (defn author-count [book]
-  :-)
+  (count (:authors book)))
+
+; (author-count cities)         ;=> 1
+; (author-count wild-seed)      ;=> 1
+; (author-count little-schemer) ;=> 2
 
 (defn multiple-authors? [book]
-  :-)
+  (< 1 (author-count book)))
+
+; (multiple-authors? cities)         ;=> false
+; (multiple-authors? wild-seed)      ;=> false
+; (multiple-authors? little-schemer) ;=> true
 
 (defn add-author [book new-author]
-  :-)
+  (let [authors-new (conj (:authors book) new-author)
+        book-new (assoc book :authors authors-new)]
+    book-new))
+
+;(add-author little-schemer {:name "Gerald J. Sussman"})
+;=> {:title "The Little Schemer"
+;    :authors [{:birth-year 1944, :name "Daniel Friedman"}
+;              {:name "Matthias Felleisen"}
+;              {:name "Gerald J. Sussman"}]}
+;(add-author {:authors [{:name "Juhana"}]} {:name "Jani"})
+;=> {:authors [{:name "Juhana"} {:name "Jani"}]}
 
 (defn alive? [author]
-  :-)
+  (not (contains? author :death-year)))
+
+;(alive? china)   ;=> true
+;(alive? octavia) ;=> false
 
 (defn element-lengths [collection]
-  :-)
+  (map count collection))
+
+; (element-lengths ["foo" "bar" "" "quux"])  ;=> (3 3 0 4)
+; (element-lengths ["x" [:a :b :c] {:y 42}]) ;=> (1 3 1)
 
 (defn second-elements [collection]
-  :-)
+  (let [second (fn [vector] (get vector 1))]
+    (map second collection)))
+
+; (second-elements [[1 2] [2 3] [3 4]]) ;=> (2 3 4)
+; (second-elements [[1 2 3 4] [1] ["a" "s" "d" "f"]])
+;=> (2 nil "s")
 
 (defn titles [books]
-  :-)
+  (map :title books))
+
+; (def books [cities, wild-seed, embassytown, little-schemer])
+; (titles [cities]) ;=> ("The City and the City" )
+; (titles books)
+;=> ("The City and the City" "Wild Seed"
+;    "Embassytown" "The Little Schemer")
 
-(defn monotonic? [a-seq]
-  :-)
 
 (defn stars [n]
-  :-)
+  (apply str (repeat n \*)))
+
+; (stars 1) ;=> "*"
+; (stars 7) ;=> "*******"
+; (stars 3) ;=> "***"
+
+(defn monotonic? [a-seq]
+  (or (apply >= a-seq) (apply <= a-seq)))
+
+; (monotonic? [1 2 3])     ;=> true
+; (monotonic? [0 1 10 11]) ;=> true
+; (monotonic? [3 2 0 -3])  ;=> true
+; (monotonic? [3 2 2])     ;=> true    Not strictly monotonic
+; (monotonic? [1 2 1 0])   ;=> false
 
 (defn toggle [a-set elem]
-  :-)
+  (if (contains? a-set elem)
+    (disj a-set elem)
+    (conj a-set elem)))
+
+; (toggle #{:a :b :c} :d) ;=> #{:a :c :b :d}
+; (toggle #{:a :b :c} :a) ;=> #{:c :b}
 
 (defn contains-duplicates? [a-seq]
-  :-)
+  (not= (count a-seq) (count (set a-seq))))
+
+; (contains-duplicates? [1 1 2 3 -40]) ;=> true
+; (contains-duplicates? [1 2 3 -40]) ;=> false
+; (contains-duplicates? [1 2 3 "a" "a"]) ;=> true
 
 (defn old-book->new-book [book]
-  :-)
+  (assoc book :authors (set (:authors book))))
+
+; (old-book->new-book {:title "The Little Schemer"
+;                     :authors [friedman, felleisen]})
+;=> {:title "The Little Schemer" :authors #{friedman, felleisen}}
+; (old-book->new-book {:title "Wild Seed", :authors [octavia]})
+;=> {:title "Wild Seed", :authors #{octavia}}
+; (old-book->new-book
+;  {:awards ["Hugo" "World Fantasy Award" "Arthur C. Clarke Award"
+;            "British Science Fiction Award"]
+;   :title "The City and the City"
+;   :authors [{:birth-year 1972, :name "China Miéville"}]})
+
 
 (defn has-author? [book author]
-  :-)
+  (contains?  (:authors book) author))
+; (has-author? cities china)             ;=> true
+; (has-author? cities felleisen)         ;=> false
+; (has-author? little-schemer felleisen) ;=> true
+; (has-author? little-schemer friedman)  ;=> true
+; (has-author? little-schemer octavia)   ;=> false
+
 
 (defn authors [books]
-  :-)
+  (apply clojure.set/union (map :authors books)))
+
+; (authors [cities, wild-seed])              ;=> #{china, octavia}
+; (authors [cities, wild-seed, embassytown]) ;=> #{china, octavia}
+; (authors [little-schemer, cities])         ;=> #{china, friedman, felleisen}
+
+; (:name {:name "China Miéville", :birth-year 1972})
 
 (defn all-author-names [books]
-  :-)
+  (set (map :name (authors books))))
+
+; (all-author-names books)
+;=> #{"Matthias Felleisen" "China Miéville"
+;     "Octavia E. Butler" "Daniel Friedman"}
+; (all-author-names [cities, wild-seed])
+;=> #{"China Miéville" "Octavia E. Butler"}
+; (all-author-names []) ;=> #{}
 
 (defn author->string [author]
-  :-)
+  (let [name (str (:name author))
+        years-end (if (:death-year author) (:death-year author) (str ""))
+        years (if (:birth-year author) (str " (" (:birth-year author) " - " years-end ")") (str ""))
+        ]
+    (str name years)))
+
+; (author->string felleisen) ;=> "Matthias Felleisen"
+; (author->string friedman)  ;=> "Daniel Friedman (1944 - )"
+; (author->string octavia)   ;=> "Octavia E. Butler (1947 - 2006)"
 
 (defn authors->string [authors]
-  :-)
+  (apply str (interpose ", " (map author->string authors))))
+
+; (authors->string (:authors little-schemer))
+;=> "Daniel Friedman (1944 - ), Matthias Felleisen"
+; (authors->string #{octavia})          ;=> "Octavia E. Butler (1947 - 2006)"
+; (authors->string #{})                 ;=> ""
+; (authors->string #{octavia, friedman})
+;=> "Octavia E. Butler (1947 - 2006), Daniel Friedman (1944 - )"
+;   order doesn't matter
 
 (defn book->string [book]
-  :-)
+  (str (:title book) ", written by " (authors->string (:authors book))))
+
+; (book->string wild-seed) ;=> "Wild Seed, written by Octavia E. Butler"
+; (book->string little-schemer)
+;=> "The Little Schemer, written by Daniel Friedman (1944 - ), Matthias Felleisen"
+;                                   ^-- order doesn't matter
 
 (defn books->string [books]
-  :-)
+  (let [book-count (count books)
+        book-count-in-words (cond
+                              (= 0 book-count) "No books."
+                              (= 1 book-count) "1 book. "
+                              (< 1 book-count) (str book-count " books. ")
+                              :else "Error")
+        ]
+    (str book-count-in-words
+         (apply str (interpose ". " (map book->string books)))
+         (if (= 0 book-count) "" "."))))
+
+; (books->string []) ;=> "No books."
+; (books->string [cities])
+; (books->string [little-schemer, cities, wild-seed])
 
 (defn books-by-author [author books]
-  :-)
+  (filter (fn [book] (has-author? book author)) books))
+
+; (books-by-author china books)   ;=> (cities embassytown)
+; (books-by-author octavia books) ;=> (wild-seed)
+; (def authors #{china, felleisen, octavia, friedman})
 
 (defn author-by-name [name authors]
-  :-)
+  (let [author-match (filter (fn [author] (= (:name author) name)) authors)]
+    (first author-match)))
+
+; (author-by-name "Octavia E. Butler" authors)                ;=> octavia
+; (author-by-name "Octavia E. Butler" #{felleisen, friedman}) ;=> nil
+; (author-by-name "China Miéville" authors)                   ;=> china
+; (author-by-name "Goerge R. R. Martin" authors)              ;=> nil
 
 (defn living-authors [authors]
-  :-)
+  (filter alive? authors))
+
+; (living-authors authors)             ;=> (china, felleisen, friedman)
+; (living-authors #{octavia})          ;=> ()
+; (living-authors #{china, felleisen}) ;=> (china, felleisen)
 
 (defn has-a-living-author? [book]
-  :-)
+  (let [authors (living-authors (:authors book))]
+    (< 0 (count authors))))
+
 
 (defn books-by-living-authors [books]
-  :-)
+  (filter has-a-living-author? books))
 
 ; %________%