药剂反向连续 [英] Reverse concat in Elixir

问题描述

Elixir（或Erlang）中是否有标准库函数将其他列表前面的列表的倒数连接起来？基本上我正在Scala中找到相当于 reverse _ ::: 的等价物。

Is there a standard library function in Elixir (or Erlang) to concatenate the reverse of a list in front of some other list? Basically I'm looking for an equivalent of reverse_::: in Scala.

理由是它很方便当在列表上实现尾递归算法时。在递归期间，您可以保留一些元素，以便稍后将它们添加到累加器列表的前端。最后，您可以一次性将它们反向连接到组合列表的剩余部分（这应该是非常有效的）。

The rationale is that it's handy when implementing a tail-recursive algorithm on a list. During recursion, you hold on to some of the elements for later by adding them onto the front of an accumulator list. In the end you can reverse-concat them onto the remainder of the assembled list in one go (which should be pretty efficient).

推荐答案

p>您可以使用 在Erlang中执行反向和并发列表：reverse / 2 。

You can do a reverse and concat in Erlang by using lists:reverse/2.

我认为文档说明和示例足够清楚：

I think the documentation explanation and example are clear enough:

reverse（List1，Tail） - >列表2 。

以相反的顺序返回一个包含 List1 中的元素的列表，
尾尾部附加。

Returns a list with the elements in List1 in reverse order, with the tail Tail appended.

> lists:reverse([1, 2, 3, 4], [a, b, c]).
[4,3,2,1,a,b,c]

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