Clojure Koans Answers and Explanations - 11 - Sequence Comprehension

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

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;1

(= __

     (for [index (range 6)]

       index))

(= [0 1 2 3 4 5]

     (for [index (range 6)]

       index))

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;2

 (= '(0 1 4 9 16 25)

     (map (fn [index] (* index index))

          (range 6))

     (for [index (range 6)]

       __))

 (= '(0 1 4 9 16 25)

     (map (fn [index] (* index index))

          (range 6))

     (for [index (range 6)]

       (* index index)))

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;3

 (= '(1 3 5 7 9)

     (filter odd? (range 10))

     (for [index __ :when (odd? index)]

       index))

 (= '(1 3 5 7 9)

     (filter odd? (range 10))

     (for [index (range 10) :when (odd? index)]

       index))

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;4

 (= '(1 9 25 49 81)

     (map (fn [index] (* index index))

          (filter odd? (range 10)))

     (for [index (range 10) :when __]

       __))

 (= '(1 9 25 49 81)

     (map (fn [index] (* index index))

          (filter odd? (range 10)))

     (for [index (range 10) :when (odd? index)]

       (* index index)))

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;5

 (= [[:top :left] [:top :middle] [:top :right]

      [:middle :left] [:middle :middle] [:middle :right]

      [:bottom :left] [:bottom :middle] [:bottom :right]]

       (for [row [:top :middle :bottom] column [:left :middle :right]]

         __)))

(= [[:top :left] [:top :middle] [:top :right]

      [:middle :left] [:middle :middle] [:middle :right]

      [:bottom :left] [:bottom :middle] [:bottom :right]]

       (for [row [:top :middle :bottom] column [:left :middle :right]]

         [row column]))