java - 从具有特定值的 clojure vector 中提取 HashMap 列表

Question

我有一个包含 HashMap 的 Clojure vector 。这些 HashMap 本身不与任何键关联。但是所有这些 HashMap 都有一个共同的键 - 比方说 "ckey" 。我想提取那些 "ckey" 的 HashMap 值为 "test" .

数据实际上是解析后的json。像这样的事情:-

testdata :{
sample1 : "samplevalue1"
sample2 : "samplevalue2"
sample3 : {innersample3 : "innersamplevalue3"}
sample4 : "samplevalue4"
sample5 : [{moresample [] 
           link {innersample5 : "innersamplevalue5"} 
           ckeydata [{ckey:"test" something: somethingValue something2: somethingValue2}]}
         {moresample [] 
           link {innersample5 : "innersamplevalue5"} 
           ckeydata [{ckey:"test1"something: somethingValue something2: somethingValue2}]}
         {moresample [] 
           link {innersample5 : "innersamplevalue5"} 
           ckeydata [ {ckey:"test2" something: somethingValue something2: somethingValue2}]}
         {moresample [] 
           link {innersample5 : "innersamplevalue5"} 
           ckeydata [ {ckey:"test" something: somethingValue something2: somethingValue2}]}]}

所以在这种情况下我想从 sample5 中提取 HashMap 谁的"ckeydata" key 有一个 vector ，其中包含一个具有 "ckey" 的 HashMap 。 "test" 的值.

Clojure 格式的数据:

testdata {
    :sample1  "samplevalue1"
    :sample2  "samplevalue2"
    :sample3  {:innersample3  "innersamplevalue3"}
    :sample4  "samplevalue4"
    :sample5  [{:moresample [] 
               :link {innersample5  "innersamplevalue5"} 
               :ckeydata [{:ckey:"test" :something: somethingValue something2 somethingValue2}]}
               {:moresample [] 
                :link {innersample5  "innersamplevalue5"} 
                :ckeydata [{:ckey "test1" :something "somethingValue" :something2 "somethingValue2"}]}
               {:moresample [] 
                :link {:innersample5  "innersamplevalue5"} 
                :ckeydata [ {:ckey "test2" :something "somethingValue" :something2 "somethingValue2"}]}
               {:moresample [] 
                :link {innersample5 : "innersamplevalue5"} 
                :ckeydata [ {:ckey "test" :something  "somethingValue" :something2 "somethingValue2"}]}]}

注意:我不想使用很多过滤器并继续循环代码。

Answer 1

这应该有效:

(filter
  (fn [{:keys [ckeydata]}]
    (some (comp #{"test"} :ckey) ckeydata))
  (:sample5 testdata))

这是一个相当密集的版本:

(filter
  (fn [sample-map]
    (some
      (fn [element]
        (= (:ckey element) "test"))
      (:ckeydata sample-map)))
  (:sample5 testdata))

<小时/>

如果 :ckeydata 始终只包含一个元素，请考虑:

(filter
  (comp #{"test"} :ckey first :ckeydata)
  (:sample5 testdata))