如何在Common Lisp中基于已有列表创建新列表？

Let's break down what's happening with your code and how to get the reversed list you're aiming for.

First, the issue with your current approach: when you use ' (quote) around the list ((caddr example1) (cadr example1) (car example1)), Common Lisp treats everything inside as literal symbols—it doesn't evaluate the caddr, cadr, or car calls. So instead of getting (3 2 1), you end up with a list of unevaluated function call symbols: ((CADDR EXAMPLE1) (CADR EXAMPLE1) (CAR EXAMPLE1)).

Here are three straightforward ways to fix this:

1. Use the list function #

The list function evaluates each of its arguments and returns a new list with those evaluated values. This is the most direct way for your use case:

(setq example1 '(1 2 3))
(setq example2 (list (caddr example1) (cadr example1) (car example1)))
;; example2 will now be (3 2 1)

2. Use quasiquote (`) and unquote (,) #

If you ever need to mix literal values with evaluated expressions in a list, quasiquote (backtick) plus unquote (comma) is perfect. It lets you quote most of the list but evaluate specific parts:

(setq example1 '(1 2 3))
(setq example2 `(,(caddr example1) ,(cadr example1) ,(car example1)))
;; example2 is (3 2 1) here too

3. Use reverse for a cleaner solution #

Since you're just reversing the original list, why not use Common Lisp's built-in reverse function? It's more concise and works for any length of list:

(setq example1 '(1 2 3))
(setq example2 (reverse example1))
;; example2 is (3 2 1)

Any of these approaches will give you the expected new list based on example1.

内容的提问来源于stack exchange，提问作者jakHunter