Clojure Koans Answers and Explanations - 14 - Destructuring

Let's look at the solutions for the next of Clojure Koans -Destructuring.

; destructuring

(def test-address

  {:street-address "123 Test Lane"

   :city "Testerville"

   :state "TX"})

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;1

(= __ ((fn [[a b]] (str b a))

         [:foo :bar]))

(= ":bar:foo" ((fn [[a b]] (str b a))

         [:foo :bar])

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;2

(= (str "First comes love, "

          "then comes marriage, "

          "then comes Clojure with the baby carriage")

     ((fn [[a b c]] __)

      ["love" "marriage" "Clojure"]))

(= (str "First comes love, "

          "then comes marriage, "

          "then comes Clojure with the baby carriage")

     ((fn [[a b c]] (str "First comes " a ", then comes " b ", then comes " c " with the baby carriage"))

      ["love" "marriage" "Clojure"]))

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;3

(= "Rich Hickey aka The Clojurer aka Go Time aka Macro Killah"

     (let [[first-name last-name & aliases]

           (list "Rich" "Hickey" "The Clojurer" "Go Time" "Macro Killah")]

       __))

(= "Rich Hickey aka The Clojurer aka Go Time aka Macro Killah"

     (let [[first-name last-name & aliases]

           (list "Rich" "Hickey" "The Clojurer" "Go Time" "Macro Killah")]

       (apply str (interpose " aka " (cons (str first-name " " last-name) aliases)))))

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;4

 (= {:original-parts ["Steven" "Hawking"] :named-parts {:first "Steven" :last "Hawking"}}

     (let [[first-name last-name :as full-name] ["Steven" "Hawking"]]

       __))

(= {:original-parts ["Steven" "Hawking"] :named-parts {:first "Steven" :last "Hawking"}}

     (let [[first-name last-name :as full-name] ["Steven" "Hawking"]]

       (hash-map :original-parts full-name :named-parts (hash-map :first first-name :last last-name))))

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;5

(= "123 Test Lane, Testerville, TX"

     (let [{street-address :street-address, city :city, state :state} test-address]

       __))

(= "123 Test Lane, Testerville, TX"

     (let [{street-address :street-address, city :city, state :state} test-address]

       (apply str (interpose ", " (list street-address city state)))))

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;6

(= "123 Test Lane, Testerville, TX"

     (let [{:keys [street-address __ __]} test-address]

       __))

(= "123 Test Lane, Testerville, TX"

     (let [{:keys [street-address city state]} test-address]

       (apply str (interpose ", " (list street-address city state)))))

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;7

 (= "Test Testerson, 123 Test Lane, Testerville, TX"

     (___ ["Test" "Testerson"] test-address)))

(= "Test Testerson, 123 Test Lane, Testerville, TX"

     ((fn [[a b] {:keys [street-address city state]}]

        (apply str (interpose ", " (list (str a " " b) street-address city state))))

      ["Test" "Testerson"] test-address))