CODEWITHSUNDEEP
listdictionaryclojurenested
hawkeye
hawkeye

Reputation: 35692

Clojure - pairs from nested lists

I'm trying to make traversing nested lists to collect pairs more idiomatic in Clojure

(def mylist '(
  (2, 4, 6)
  (8, 10, 12)))

(defn pairs [[a b c]]
  (list (list a c)(list b c)))

(mapcat pairs mylist)

;((2 6) (4 6) (8 12) (10 12))

Can this be made more elegant?

Upvotes: 2

Views: 226

Answers (2)

xsc
xsc

Reputation: 6073

Just to add more solutions (not elegant or intuitive; do not use ;) ):

(mapcat
  (juxt (juxt first last) (juxt second last))
  [[2 4 6] [8 10 12]])
;; => ([2 6] [4 6] [8 12] [10 12])

Or this one:

(mapcat
  #(for [x (butlast %) y [(last %)]] [x y])
  [[2 4 6] [8 10 12]])
;; => ([2 6] [4 6] [8 12] [10 12])

Upvotes: 2

mishadoff
mishadoff

Reputation: 10789

Your code is good, but I would use vectors instead of lists

(defn pairs [[x1 x2 y]]
  [[x1 y] [x2 y]])

(mapcat pairs mylist)

Upvotes: 3

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