Question

我的小组和我正在尝试创建一份缺点列表。它可能看起来像这样

((2 100032) (4 32413) (6 2131251) ... (232 12))

不幸的是，我们不断收到＃34;错误的类型参数＆＃34;。这可能是一件简单的事情，但我也想知道我们是否在做缺点。

任何回复都表示赞赏：

(defun find-diffs ()
    (let ((diffs (list))
          (index 0)
          (previous 0))
         (while (< index (length first-ten-million-primes))
           ; Add the difference to the list of diffs.
           (setq diff (- (aref first-ten-million-primes index) previous))
           ; We only want to bother recording it if the index is above zero and
           ; the difference is odd.
           (if (and (> index 0) (evenp diff))
             (setq diffs
               ; Can we find this one in our list of diffs?
               (if (cdr (assoc diff diffs))

                 ; Yes
                 ; ERROR happens when we call this statement
                 (setq diffs 
                   (append (cons diff (1+ (car (cdr (assq diff diffs)))))
                           (assq-delete-all diff diffs)))
                 ; No
                 (setq diffs (plist-put diffs diff 1)))))
           ; Set previous value to this one.
           (setq previous (aref first-ten-million-primes index))
           ; Increment the index.
           (setq index (1+ index)))
         diffs)

评论（setq diffs）将解决它，但我没有看到我们如何设置变量有什么问题。

谢谢！

回溯很大，所以我只发布第一部分。我的团队仍然对于什么是错误感到困惑，所以任何回复都会受到赞赏。

调试器Backtrace：

Debugger entered--Lisp error: (wrong-type-argument listp 1)
  append((2 . 1) nil)
  (setq diffs (append (cons diff 1) diffs))
  (if (cdr (assoc diff diffs)) (setq diffs (append (cons diff (1+ (car (cdr (assq diff diffs)))))

Answer 1

您的问题出在：

               (append (cons diff (1+ (car (cdr (assq diff diffs)))))
                       (assq-delete-all diff diffs)))

cons向上创建(DIFF . N)形式的单元格，该单元格不是正确的列表。它是一对两个元素而不是两个元素的列表。两个元素的列表的格式为(DIFF N)，这是(DIFF . (N . nil))的简写。

我没有尝试了解您的总体目标是什么，但有两种方法可以解决您的问题：要么替换

(append (cons diff FOO)
        ...)

与

(append (list diff FOO)
        ...)

或

(cons (cons diff FOO)
      ...)

setq：错误类型参数：listp 1

1 个答案: