如何在中使用assoc更新映射中的多个值？（Clojure）

我正在尝试更新每一行有“享受clojure？”的内容，该内容将真实的“理智评级”返回到-2（即johnny的理智评级将更新为-2）

我是Clojure新手，曾尝试研究update和assoc，但似乎无法找到更新多个元素的方法（

（assoc学生数据库[0:SanityRating]-2）

仅返回一个元素的更新）。要筛选学生数据库以取出返回true的学生，我有

(defn unhinged?
 [record]
 (:enjoy-clojure? record))

(defn minus-two-students
 [student-database]
 (filter #(unhinged? %)
  (map student-database [0 1 2 3 4])))

返回

({:enjoy-clojure? true, :name "johnny", :sanity-rating 2} {:enjoy-clojure? 
   true, :name "jilly", :sanity-rating 5} {:enjoy-clojure? true, :name 
   "janey", :sanity-rating 8})

---

这很好，但我也需要它来更新他们所有的理智评级为-2。如有任何帮助/提示，将不胜感激

现在是

reduce kv

版本

(defn adjust-sanity [student]
  (if (:enjoy-clojure? student)
    (assoc student :sanity-rating -2)
    student))

(reduce-kv (fn [m k v] (assoc m k (adjust-sanity v)))
           {}
           student-database)
=>
{0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9},
 1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2},
 2 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2},
 3 {:enjoy-clojure? true, :name "janey", :sanity-rating -2},
 4 {:enjoy-clojure? false, :name "jelly", :sanity-rating 10}}

或另一个带有辅助函数的选项，用于更新地图的所有值：

(defn update-vals [m f]
  (reduce-kv (fn [m' k v] (assoc m' k (f v))) {} m))
(update-vals student-database adjust-sanity)

---

下面是

reduce kv

版本

(defn adjust-sanity [student]
  (if (:enjoy-clojure? student)
    (assoc student :sanity-rating -2)
    student))

(reduce-kv (fn [m k v] (assoc m k (adjust-sanity v)))
           {}
           student-database)
=>
{0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9},
 1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2},
 2 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2},
 3 {:enjoy-clojure? true, :name "janey", :sanity-rating -2},
 4 {:enjoy-clojure? false, :name "jelly", :sanity-rating 10}}

或另一个带有辅助函数的选项，用于更新地图的所有值：

(defn update-vals [m f]
  (reduce-kv (fn [m' k v] (assoc m' k (f v))) {} m))
(update-vals student-database adjust-sanity)

---

要更新整个数据库，可以执行以下操作：

(def student-database
  {0 {:enjoy-clojure? false, :name "jimmy",:sanity-rating 9}
   1 { :enjoy-clojure? true, :name "johnny",:sanity-rating 2}
   2 { :enjoy-clojure? true, :name "jilly",:sanity-rating 5}
   3 { :enjoy-clojure? true, :name "janey",:sanity-rating 8}
   4 {:enjoy-clojure? false, :name "jelly",:sanity-rating 10}})

(defn update-db [db]
  (zipmap (keys db)
          (map (fn [student]
                 (cond-> student
                   (:enjoy-clojure? student)
                   (assoc :sanity-rating -2)))
               (vals db))))

(update-db student-database) ;;=> 
{0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9}, 
 1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2} ...}

---

要更新整个数据库，可以执行以下操作：

(def student-database
  {0 {:enjoy-clojure? false, :name "jimmy",:sanity-rating 9}
   1 { :enjoy-clojure? true, :name "johnny",:sanity-rating 2}
   2 { :enjoy-clojure? true, :name "jilly",:sanity-rating 5}
   3 { :enjoy-clojure? true, :name "janey",:sanity-rating 8}
   4 {:enjoy-clojure? false, :name "jelly",:sanity-rating 10}})

(defn update-db [db]
  (zipmap (keys db)
          (map (fn [student]
                 (cond-> student
                   (:enjoy-clojure? student)
                   (assoc :sanity-rating -2)))
               (vals db))))

(update-db student-database) ;;=> 
{0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9}, 
 1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2} ...}

---

最简单的方法如下：

(reduce-kv (fn [acc idx row]
             (assoc acc idx
                    (if (:enjoy-clojure? row)
                      (assoc row :sanity-rating -2)
                      row)))
           {}
           student-database)

;;=> {0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9}, 
;;    1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2}, 
;;    2 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2}, 
;;    3 {:enjoy-clojure? true, :name "janey", :sanity-rating -2}, 
;;    4 {:enjoy-clojure? false, :name "jelly", :sanity-rating 10}}

(reduce-kv (fn [res k {ec? :enjoy-clojure?}]
             (if ec?
               (assoc-in res [k :sanity-rating] -2)
               res))
           student-database
           student-database)

;;=> {0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9}, 
;;    1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2}, 
;;    2 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2}, 
;;    3 {:enjoy-clojure? true, :name "janey", :sanity-rating -2}, 
;;    4 {:enjoy-clojure? false, :name "jelly", :sanity-rating 10}}

您也可以这样做：

(reduce-kv (fn [acc idx row]
             (assoc acc idx
                    (if (:enjoy-clojure? row)
                      (assoc row :sanity-rating -2)
                      row)))
           {}
           student-database)

;;=> {0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9}, 
;;    1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2}, 
;;    2 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2}, 
;;    3 {:enjoy-clojure? true, :name "janey", :sanity-rating -2}, 
;;    4 {:enjoy-clojure? false, :name "jelly", :sanity-rating 10}}

(reduce-kv (fn [res k {ec? :enjoy-clojure?}]
             (if ec?
               (assoc-in res [k :sanity-rating] -2)
               res))
           student-database
           student-database)

;;=> {0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9}, 
;;    1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2}, 
;;    2 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2}, 
;;    3 {:enjoy-clojure? true, :name "janey", :sanity-rating -2}, 
;;    4 {:enjoy-clojure? false, :name "jelly", :sanity-rating 10}}

---

最简单的方法如下：

(reduce-kv (fn [acc idx row]
             (assoc acc idx
                    (if (:enjoy-clojure? row)
                      (assoc row :sanity-rating -2)
                      row)))
           {}
           student-database)

;;=> {0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9}, 
;;    1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2}, 
;;    2 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2}, 
;;    3 {:enjoy-clojure? true, :name "janey", :sanity-rating -2}, 
;;    4 {:enjoy-clojure? false, :name "jelly", :sanity-rating 10}}

(reduce-kv (fn [res k {ec? :enjoy-clojure?}]
             (if ec?
               (assoc-in res [k :sanity-rating] -2)
               res))
           student-database
           student-database)

;;=> {0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9}, 
;;    1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2}, 
;;    2 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2}, 
;;    3 {:enjoy-clojure? true, :name "janey", :sanity-rating -2}, 
;;    4 {:enjoy-clojure? false, :name "jelly", :sanity-rating 10}}

您也可以这样做：

(reduce-kv (fn [acc idx row]
             (assoc acc idx
                    (if (:enjoy-clojure? row)
                      (assoc row :sanity-rating -2)
                      row)))
           {}
           student-database)

;;=> {0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9}, 
;;    1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2}, 
;;    2 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2}, 
;;    3 {:enjoy-clojure? true, :name "janey", :sanity-rating -2}, 
;;    4 {:enjoy-clojure? false, :name "jelly", :sanity-rating 10}}

(reduce-kv (fn [res k {ec? :enjoy-clojure?}]
             (if ec?
               (assoc-in res [k :sanity-rating] -2)
               res))
           student-database
           student-database)

;;=> {0 {:enjoy-clojure? false, :name "jimmy", :sanity-rating 9}, 
;;    1 {:enjoy-clojure? true, :name "johnny", :sanity-rating -2}, 
;;    2 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2}, 
;;    3 {:enjoy-clojure? true, :name "janey", :sanity-rating -2}, 
;;    4 {:enjoy-clojure? false, :name "jelly", :sanity-rating 10}}

---

您在问题中没有说您希望函数只返回

（=享受clojure？true）

记录，但从您在其他答案中的注释来看，我觉得这才是您真正想要的

那么也许是这个

(defn unhinged?
  [record]
  (:enjoy-clojure? record))

(defn minus-two-students
  [student-database]
  (->> student-database
       vals
       (filter unhinged?)
       (map #(assoc % :sanity-rating -2))))

输出将是

({:enjoy-clojure? true, :name "johnny", :sanity-rating -2} 
 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2} 
 {:enjoy-clojure? true, :name "janey", :sanity-rating -2})

---

您在问题中没有说您希望函数只返回

（=享受clojure？true）

记录，但从您在其他答案中的注释来看，我觉得这才是您真正想要的

那么也许是这个

(defn unhinged?
  [record]
  (:enjoy-clojure? record))

(defn minus-two-students
  [student-database]
  (->> student-database
       vals
       (filter unhinged?)
       (map #(assoc % :sanity-rating -2))))

输出将是

({:enjoy-clojure? true, :name "johnny", :sanity-rating -2} 
 {:enjoy-clojure? true, :name "jilly", :sanity-rating -2} 
 {:enjoy-clojure? true, :name "janey", :sanity-rating -2})

---

太好了！这会打印出每个人，我可以只打印“享受clojure？真的”学生吗？当然，只需将

（map…

参数设置为

zipmap

，然后将

map

更改为

过滤器即可。谢谢！我还不太熟悉zipmap，所以我很抱歉，但是我该如何将
（map…
参数带到
zipmap
？我在做类似于
（zipmap（key db[01 2 3 4]）
？我知道这不起作用，但仍在努力学习这种语言，我的意思是：（filter（fn[student]（cond->student）（享受clojure？student）（assoc:sanity rating-2））（VAL学生数据库））太好了！这打印出了所有人，我能只打印出“享受clojure？真的”学生吗？当然，只要把
（map…
参数带到
zipmap
，然后将
map
更改为
过滤器
。谢谢！我对zipmap还不太熟悉，所以我很抱歉，但是我到底要如何带
（map…）
zipmap的参数

？我是否在做类似于

（zipmap（键db[0 1 2 3 4]）

？我知道这不起作用，但仍在努力学习这门语言我的意思是：（filter（fn[student]（cond->student）（享受clojure？student）（assoc:sanity rating-2）））（VAL学生数据库）太好了！这可以打印出每个人，有没有办法只打印出“享受clojure？真”的学生，而不打印假学生？@Student1860

（->（更新VAL学生数据库调整理智）（VAL）（筛选：享受clojure？）

那太好了！这打印出了每个人，有没有一种方法我可以只打印出“享受clojure？真”的学生，而不打印假学生？@Student1860

（（->）（更新VAL学生数据库调整理智）（VAL）（筛选：享受clojure？）

啊，实际上我正在将他们的值设置为“-2”不是用它来减少它们。不过谢谢！我实际上是把它们设置为“-2”的值，不是用它来减少它们。不过谢谢！