你如何复制Common Lisp中的数组？ [英] How do you copy an array in common lisp?

问题描述

我想使我的二维数组，这感觉就像是不错的，功能性的，非破坏性的处理方式阵列的副本。什么是这样做的lispy方式？

I'd like to make copies of my 2D array, which feels like the nice, functional, nondestructive way of handling arrays. What is the lispy way of doing this?

推荐答案

我用下面的，我相信这是比亚历山大更好的版本：

I use the following, which I believe is better than the alexandria version:

(defun copy-array (array &key
                   (element-type (array-element-type array))
                   (fill-pointer (and (array-has-fill-pointer-p array)
                                      (fill-pointer array)))
                   (adjustable (adjustable-array-p array)))
  "Returns an undisplaced copy of ARRAY, with same fill-pointer and
adjustability (if any) as the original, unless overridden by the keyword
arguments."
  (let* ((dimensions (array-dimensions array))
         (new-array (make-array dimensions
                                :element-type element-type
                                :adjustable adjustable
                                :fill-pointer fill-pointer)))
    (dotimes (i (array-total-size array))
      (setf (row-major-aref new-array i)
            (row-major-aref array i)))
    new-array))

与亚历山大的版本问题是，调整阵列
黑客导致的结果（至少在SBCL）永远不会成为一个
简单阵列，其中一些其他库（例如opticl）的期望。该
以上版本还对我更快。

The problem with the alexandria version is that the adjust-array hack causes the result (at least on SBCL) to never be a simple-array, which some other libraries (e.g. opticl) expect. The above version also was faster for me.

别人在不同出版了一本非常类似的版本
图书馆，但我忘了的人都和库的名称。

Someone else has published a very similar version in a different library, but I forgot the names of both person and library.

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