如何在clojure中将一个键分配给一个向量的每个项目？

Question

如果我这样做,我可以使用什么功能:

(the-function :a [1 2 3 4 5])

我明白了: [{:a 1} {:a 2} {:a 3} {:a 4} {:a 5}]

谢谢你的回答!

Answer 1

有几种表达方式:

user> (defn the-function [key vals] (map hash-map (repeat key) vals)) 
#'user/the-function    
user> (the-function :a [1 2 3 4 5])      
({:a 1} {:a 2} {:a 3} {:a 4} {:a 5})  

要么

user> (defn the-function [key vals] (map (partial hash-map key)  vals))
#'user/the-function
user> (the-function :a [1 2 3 4 5])
({:a 1} {:a 2} {:a 3} {:a 4} {:a 5})

或者用于代替地图:

user> (defn the-function [key vals] (for [val vals] {key val}))
#'user/the-function
user> (the-function :a [1 2 3 4 5])
({:a 1} {:a 2} {:a 3} {:a 4} {:a 5})

这些返回序列,如果它需要是一个向量,您可以将它们包装在调用vec或使用mapv中:

user> (defn the-function [key vals] (mapv (partial hash-map key)  vals))
#'user/the-function
user> (the-function :a [1 2 3 4 5])
[{:a 1} {:a 2} {:a 3} {:a 4} {:a 5}]
user> (the-function :a `(1 2 3 4 5))
[{:a 1} {:a 2} {:a 3} {:a 4} {:a 5}]