如何在 Clojure 中过滤持久映射? [英] How to filter a persistent map in Clojure?

问题描述

我有一个要过滤的永久地图.像这样:

I have a persistent map which I want to filter. Something like this:

(filter #(-> % val (= 1)) {:a 1 :b 1 :c 2})

上面的结果是 ([:a 1] [:b 1]) (一个懒惰的地图条目序列).但是我想得到 {:a 1 :b 1}.

The above comes out as ([:a 1] [:b 1]) (a lazy sequence of map entries). However I want to be get {:a 1 :b 1}.

如何过滤地图以使其保持地图状态，而不必从一系列地图条目中重建它?

How can I filter a map so it remains a map without having to rebuild it from a sequence of map entries?

推荐答案

还有一个:

(let [m {:a 1 :b 2 :c 1}]
  (select-keys m (for [[k v] m :when (= v 1)] k)))

这篇关于如何在 Clojure 中过滤持久映射?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！