在Clojure中创建地图条目 [英] Create a map entry in Clojure

问题描述

创建单个地图条目的内置 Clojure方法是什么？

What is the built-in Clojure way (if any), to create a single map entry?

换句话说，我想要（地图输入键值）之类的东西。换句话说，结果应大致等于（第一个{键值}）。

In other words, I would like something like (map-entry key value). In other words, the result should be more or less equivalent to (first {key value}).

备注：

• 当然，我已经尝试了谷歌搜索，只发现了地图条目？但是，该文档没有链接的资源。


• 我知道（第一个{1 2}）返回 [1 2] ，这似乎是一个向量。但是：

• Of course, I already tried googling, and only found map-entry? However, this document has no linked resources.
• I know that (first {1 2}) returns [1 2], which seems a vector. However:

(class (first {1 2}))
; --> clojure.lang.MapEntry
(class [1 2])
; --> clojure.lang.PersistentVector

• 我检查了源代码，然后知道 MapEntry 和 PersistentVector 扩展 APersistentVector （所以 MapEntry 还是一个向量）。但是，问题仍然是，我是否可以根据Clojure代码创建 MapEntry 实例。


• 最后，但并非最不重要的是：否，在Clojure中没有内置的方法可以做到这一点（这也是一个有效的答案（我非常怀疑是这种情况，只是想确保我没有偶然错过任何事情）。


• I checked in the source code, and I'm aware that both MapEntry and PersistentVector extend APersistentVector (so MapEntry is more-or-less also a vector). However, the question is still, whether I can create a MapEntry instance from Clojure code.
• Last, but not least: "no, there is no built in way to do that in Clojure" is also a valid answer (which I strongly suspect is the case, just want to make sure that I did not accidentally miss something).

推荐答案




不，在Clojure中没有内置的方法可以做到这一点也是有效的答案

"no, there is no built in way to do that in Clojure" is also a valid answer

是的，很不幸，这就是答案。我想说的是，您可以做的最好的事情就是自己定义 map-entry 函数：

Yeah, unfortunately that's the answer. I'd say the best you can do is define a map-entry function yourself:

(defn map-entry [k v]
  (clojure.lang.MapEntry/create k v))

这篇关于在Clojure中创建地图条目的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！