shigemk2 https://blog.hatena.ne.jp/shigemk2/ by shigemk2 https://www.shigemk2.com/ 読書ノート = は数が等しいかどうかを調べるものなので、 シンボルと比較するとエラーになる [1]> (defun member$ (item list) (if (null lst) nil (if (= item (first lst)) lst (member$ item (rest lst))))) MEMBER$ [2]> (member$ 'tea '(juice tea coffee)) *** - IF: variable LST has no value The following restarts are available: USE-VALUE :R1 Input a value t… 190 <iframe src="https://hatenablog-parts.com/embed?url=https%3A%2F%2Fwww.shigemk2.com%2Fentry%2F20130421%2F1366515003" title="対話によるCommon Lisp入門 38 member その3 - by shigemk2" class="embed-card embed-blogcard" scrolling="no" frameborder="0" style="display: block; width: 100%; height: 190px; max-width: 500px; margin: 10px 0px;"></iframe> Hatena Blog https://hatena.blog 2013-04-21 12:30:03 rich https://www.shigemk2.com/entry/20130421/1366515003 1.0 100%