Clojure：在通过谓词真值测试的集合中找到第一个出现的事件

Question

Is there a function in Clojure that works as described in the title:

Consider this vector:

(def v [{:a 0 :b 1} {:a 0 :b 3} {:a 0 :b 2}])

I'm, trying to catch the first entry, in which :b equals 3.

Usage would be like so: (this is how the JS-underscore find works)

(myfind #(= (:b %) 3) v)

Answer 1

Naive solution:

(first (filter #(= (:b %) 3) v))

Idiomatic solution:

(some #(when (= (:b %) 3) %) v)

As a function:

(defn myfind [pred coll]                                                                                                          
  (some #(when (pred %) %) coll))

(myfind #(= (:b %) 3) v) => {:b 3, :a 0}

Answer 2

Anton:

You did not specific if you wanted to return the whole map that matches or some value for a key. Otherwise:

(filter #(= (:b %) 3)  [{:a 0 :b 1} {:a 0 :b 3} {:a 0 :b 2}])
=> ({:a 0, :b 3})