CODEWITHSUNDEEP
refactoringclojure
Fredrik
Fredrik

Reputation: 4171

Can you help me refactor this piece of clojure code to produce a seq?

I want to produce a seq that I can later do a (map) over. It should look like this:

((0 0) (0 1) (0 2) (0 3) ... (7 7))

The piece of code I have to do it right now seems very, very ugly to produce such a simple result. I need some help getting this straight.

(loop [y 0 x 0 args (list)]  
  (if (and (= y 7) (= x 7))  
    (reverse (conj args (list y x)))  
    (if (= x 7)  
    (recur (+ y 1) 0 (conj args (list y x)))  
    (recur y (+ x 1) (conj args (list y x))))))

Upvotes: 2

Views: 173

Answers (2)

2daaa
2daaa

Reputation: 2868

There's a library function that does that:

(use '[clojure.contrib.combinatorics])
(cartesian-product (range 0 8) (range 0 8))

Upvotes: 5

koddo
koddo

Reputation: 3408

(let [my-range (range 0 8)]
  (for [i my-range
        j my-range]
      (list i j)))


=> ((0 0) (0 1) (0 2) (0 3) (0 4) (0 5) (0 6) (0 7)
    (1 0) (1 1) (1 2) (1 3) (1 4) (1 5) (1 6) (1 7)
    ...
    (7 0) (7 1) (7 2) (7 3) (7 4) (7 5) (7 6) (7 7))

for is like doseq, but it collects results:

(for   [i [1 2 3]] i)           => (1 2 3)
(doseq [i [1 2 3]] (print i))   => nil

Upvotes: 13

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