更新Clojure中的层次/树结构
我有一个原子,像x:更新Clojure中的层次/树结构,clojure,tree,Clojure,Tree,我有一个原子,像x: (def x (atom {:name "A" :id 1 :children [{:name "B" :id 2 :children []} {:name "C" :id 3
(def x (atom {:name "A"
:id 1
:children [{:name "B"
:id 2
:children []}
{:name "C"
:id 3
:children [{:name "D" :id 4 :children []}]}]}))
需要更新submap,例如:
if :id is 2 , change :name to "Z"
产生更新的Atom:
{:name "A"
:id 1
:children [{:name "Z"
:id 2
:children []}
{:name "C"
:id 3
:children [{:name "D" :id 4 :children []}]}]}
如何做到这一点?您可以使用名称空间或从名称空间中执行
(def x (atom {:name "A"
:id 1
:children [{:name "B"
:id 2
:children []}
{:name "C"
:id 3
:children [{:name "D" :id 4 :children []}]}]}))
(defn update-name [x]
(if (and (map? x) (= (:id x) 2))
(assoc x :name "Z")
x))
(swap! x (partial clojure.walk/postwalk update-name))
您还可以使用
clojure.zip
命名空间中的Zippers
在此处查找工作示例:将更新拆分为一个函数,返回新映射:(defn update nested map[search key search val add map nm]“查找包含搜索键search val的映射,并将此映射与add map合并。”(postwalk(fn[x](if(and(map?x))(=(search key x)搜索值(val))(合并x添加地图)x))nm)