Clojure Zipper在异构树上

时间:2012-09-19 19:32:45

标签: clojure functional-programming zipper

我在编写可以遍历异构节点树的拉链时遇到问题。我有一张地图清单。每个地图都有ii)一个:输入键,其值是一个地图列表。

我想使用拉链访问每个叶子并添加计算值。代码块和输入树数据如下。我似乎无法获取拉链代码来访问叶节点,并添加{:thing 123}。我一定很遗憾。任何见解?

A)

      (loop [loc (zip/zipper  (or map? list?)
                              #((if (map? %1)              ;; get children of a node
                                  (:inputs %1)
                                  %1 ))
                              #(%1)                            ;; create a new node 
                              (:input-layer neural-network)) ] 

        (if (zip/end? loc) 
          (zip/root loc) 
          (if (map? loc) 
            (recur  (zip/next 
                      (zip/edit loc merge { :thing 123 } ))) 
            (recur (zip/next loc)) 
          ) 
        ) 
      ) 

B)


     ({:inputs
       ({:key :avolume, :value 2.25, :weight 0.4283380545172636, :bias 0}
        {:key :bvolume, :value 3.0, :weight 0.6970037374879661, :bias 0}
        {:key :ask, :value 1.32379, :weight 0.5387437158323669, :bias 0}
        {:key :bid, :value 1.3239, :weight 0.4648184032361037, :bias 0}
        {:key :time, :value 1.335902400676, :weight 0.43632873607404554, :bias 0}),
       :id "583c10bfdbd326ba34aed329139df6be2487ffc"}
      {:inputs
       ({:key :avolume, :value 2.25, :weight 0.13162215440222336, :bias 0}
        {:key :bvolume, :value 3.0, :weight 0.23886901184352727, :bias 0}
        {:key :ask, :value 1.32379, :weight 0.8408470512339872, :bias 0}
        {:key :bid, :value 1.3239, :weight 0.27071013797961796, :bias 0}
        {:key :time, :value 1.335902400676, :weight 0.6304505838898373, :bias 0}),
       :id "583c10bfdbd326ba34aed329139df6be2487ffd"}
      {:inputs
       ({:key :avolume, :value 2.25, :weight 0.8236972641966921, :bias 0}
        {:key :bvolume, :value 3.0, :weight 0.32421537754016705, :bias 0}
        {:key :ask, :value 1.32379, :weight 0.966306328543246, :bias 0}
        {:key :bid, :value 1.3239, :weight 0.8891668220470931, :bias 0}
        {:key :time, :value 1.335902400676, :weight 0.278993745549462, :bias 0}),
       :id "583c10bfdbd326ba34aed329139df6be2487ffe"}
      {:inputs
       ({:key :avolume, :value 2.25, :weight 0.27388486254027167, :bias 0}
        {:key :bvolume, :value 3.0, :weight 0.33659579299487363, :bias 0}
        {:key :ask, :value 1.32379, :weight 0.16610378593177033, :bias 0}
        {:key :bid, :value 1.3239, :weight 0.6964784902474896, :bias 0}
        {:key :time, :value 1.335902400676, :weight 0.6306732906337643, :bias 0}),
       :id "583c10bfdbd326ba34aed329139df6be2487fff"}
      {:inputs
       ({:key :avolume, :value 2.25, :weight 0.8819171698935051, :bias 0}
        {:key :bvolume, :value 3.0, :weight 0.5944805362120958, :bias 0}
        {:key :ask, :value 1.32379, :weight 0.9060962647355373, :bias 0}
        {:key :bid, :value 1.3239, :weight 0.37647418075176464, :bias 0}
        {:key :time, :value 1.335902400676, :weight 0.7797681719480866, :bias 0}),
       :id "583c10bfdbd326ba34aed329139df6be2488000"})

谢谢

1 个答案:

答案 0 :(得分:5)

我认为创建新节点的拉链部分是不正确的。如果您阅读definition of zipper function,您会看到make-node被调用了2个参数:当前节点,新子节点序列。函数应返回新节点。

您使用#(%1)的表达式根本不起作用,因为您尝试将map或list称为函数。

表达式(or map? list?)并不能真正做到你想做的事。


我将它改编为适合测试的载体。

(defn mk-zip [root]
  (let [branch? (fn [node]
                  (when node
                    (or (and (map? node) (contains? node :inputs))
                        (vector? node))))
        children (fn [node]
                   (cond 
                     (nil? node) nil
                     (map? node) (:inputs node)
                     :else node))
        make-node (fn [node children]
                    (cond
                      (nil? node) nil
                      (map? node) (assoc node :inputs children)
                      (vector? node) (into [] children)
                      :else node))]
    (zip/zipper branch? children make-node root)))

(def root [{:inputs
            [{:key :avolume, :value 2.25, :weight 0.4283380545172636, :bias 0}
             {:key :bvolume, :value 3.0, :weight 0.6970037374879661, :bias 0}
             {:key :ask, :value 1.32379, :weight 0.5387437158323669, :bias 0}
             {:key :bid, :value 1.3239, :weight 0.4648184032361037, :bias 0}
             {:key :time, :value 1.335902400676, :weight 0.43632873607404554, :bias 0}],
            :id "583c10bfdbd326ba34aed329139df6be2487ffc"}])

现在更新地图项目有效:

(def z (mk-zip root))
(-> z zip/next zip/down 
    (zip/insert-right {:key :new :value -10}) 
    zip/up
    zip/node)

打印:

{:inputs
 ({:key :avolume, :weight 0.4283380545172636, :bias 0, :value 2.25}
  {:key :new, :value -10}
  {:key :bvolume, :weight 0.6970037374879661, :bias 0, :value 3.0}
  {:key :ask, :weight 0.5387437158323669, :bias 0, :value 1.32379}
  {:key :bid, :weight 0.4648184032361037, :bias 0, :value 1.3239}
  {:key :time,
   :weight 0.43632873607404554,
   :bias 0,
   :value 1.335902400676}),
 :id "583c10bfdbd326ba34aed329139df6be2487ffc"}