dictionary - 在 map 中反向查找

Question

我必须使用值从映射中提取键。除了自己实现反向查找之外，还有其他方法可以做到这一点吗？

Answer 1

我认为 map-invert 是执行此操作的正确方法。

From the docs:

;; Despite being in clojure.set, this has nothing to do with sets. 

user=> (map-invert {:a 1, :b 2})
{2 :b, 1 :a}

;; If there are duplicate keys, one is chosen:

user=> (map-invert {:a 1, :b 1})
{1 :b}

;; I suspect it'd be unwise to depend on which key survives the clash.