data-structures - 在clojure中反转 HashMap

Question

我在 clojure 中有 HashMap :

{"key1" "value1"} {"key2" "value2"} {"key3" "value1"}

我需要把它转换成散列图

{"value1" {"key1" "key3"}} {"value2" {"key2"}}

任何 clojure 方法可以做到这一点？

clojure.set/map-invert 不会像覆盖重复值一样工作。

Answer 1

(def m {"key1" "value1" "key2" "value2" "key3" "value1"})

(let [g (group-by val m)
      vals (map #(map first %) (vals g))]
  (zipmap (keys g) vals))
;;=> {"value2" ("key2"), "value1" ("key1" "key3")}