list with initial-element are start from 99 to 0 in Lisp

问题

Function that takes a positive number and creates a list of all numbers between 0 (included) and the number passed as an argument (excluded). By default, it's 100

(defun list-numbers (&optional (n 100))
  (mapcar #'abs (make-list n :initial-element (- n 1))))

if you want to see the result https://ideone.com/Jbz5u3

(99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99 99)

but my goal is create a simple list that initial-element are started with values ​​from 99 to 0

(99 98 97 96 95 94 93 92 91 90 89 88 87 86.... 9 8 7 6 5 4 3 2 1 0)

回答1:

CL-USER 160 > (loop for i from 99 downto 0 collect i)
(99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0)

or

CL-USER 167 > (do* ((i      0        (+ i 1))
                    (result (list i) (cons i result)))
                   ((= i 99) result))
(99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 80 79 78 77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0)

来源：https://stackoverflow.com/questions/59039638/list-with-initial-element-are-start-from-99-to-0-in-lisp