Question

我有这样的矢量结构......

[{:email "email@gmail.com", :password "pass"} 
 {:email "email2@yahoo.com", :password "pass2"} 
 {:email "email3@yahoo.com", :password "pass3"} 
 {:email "email4@gmail.com", :password "pass4"}]

我怎样才能制作出这样的地图？两个电子邮件值必须相同......

 {{"email@gmail.com"{:email "email@gmail.com", :password "pass"}}, 
  {"email2@yahoo.com"{:email "email2@yahoo.com", :password "pass2"}}, 
  {"email3@yahoo.com" {:email "email3@yahoo.com", :password "pass3"}} ,
  {"email4@gmail.com"{:email "email4@gmail.com", :password "pass4"}}

我对clojure有点新意，所以感谢任何帮助。

Answer 1

(def a [{:email "email@gmail.com", :password "pass"}
        {:email "email2@yahoo.com", :password "pass2"}
        {:email "email3@yahoo.com", :password "pass3"}
        {:email "email4@gmail.com", :password "pass4"}])

(zipmap (map :email a) a)

创建一系列电子邮件地址，然后将原始地图的矢量拉伸到新地图中，地址为关键字，原始地图为值。

（想想左边垂直显示的电子邮件列表，右边是垂直显示的原始地图条目，还有一个拉链向下移动，将它们连接在一起）

Answer 2

另一种选择（虽然你的输出将嵌套在一个向量中）是使用group-by：

user=> (def a [{:email "email@gmail.com", :password "pass"}
        {:email "email2@yahoo.com", :password "pass2"}
        {:email "email3@yahoo.com", :password "pass3"}
        {:email "email4@gmail.com", :password "pass4"}])
#'user/a
user=> (group-by :email a)
{"email@gmail.com" [{:email "email@gmail.com", :password "pass"}], "email2@yahoo.com" [{:email "email2@yahoo.com", :password "pass2"}], "email3@yahoo.com" [{:email "email3@yahoo.com", :password "pass3"}], "email4@gmail.com" [{:email "email4@gmail.com", :password "pass4"}]}
user=>

Clojure地图嵌套

2 个答案: