Re: How could I modify list element?

[Andreas Politz]

richardeng wrote:
> Hi all,
>     setcar/setcdr is not convenient.
>     In a long list, ex.
>     (setq a '(a b c d e f g))
>     I want to change 'e to 'E.
>     I need a function: (set-list-elt list old-elt new-elt)
>
>     How? translate list to vector, modify, then turn it back???
>
>  

Why don't you ...

(let ((list  '(a b c d e)))
  (or
   (and (require 'cl nil t)
        (substitute 'E 'e list))
   (mapcar #'(lambda (elt)
               (if (eq elt 'e) 'E elt))
           list)))

-ap