在Clojure中，如何选择并返回集合的子集

Question

If I have a collection like this

{{:A "a" :B "b"} {:A "a" :B "Goal" } {:A "a" :B "Goal"}}

how do I make a function so it returns only the parts where :B "Goal" ? Meaning only:

{{:A "a" :B "Goal" } {:A "a" :B "Goal"}}

Answer 1

I fixed your data to make it a vector of 3 maps.

(def data [{:A "a" :B "b"}
           {:A "a" :B "Goal"}
           {:A "a" :B "Goal"}])

(defn b-goal?
  [item]
  (= (:B item) "Goal") )

(filter b-goal? data) => ({:A "a", :B "Goal"} {:A "a", :B "Goal"})

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