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methylene/invert_map.clj

Created January 15, 2014 16:38
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clojure invert multi-valued map
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invert_map.clj
(defn invert-map [m]
(reduce-kv
(fn [acc k v]
(merge-with (comp vec concat)
acc
(apply array-map (interleave v (repeat [k])))))
{} m))
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(invert-map {:a [:foo :bar] :b [:baz] :c [:baz]})
;; => {:baz [:c :b], :bar [:a], :foo [:a]}

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