From: Alan Mackenzie <acm@muc.de>
To: richardeng <richardeng@foxmail.com>
Cc: help-gnu-emacs@gnu.org
Subject: Re: How could I modify list element?
Date: 9 Dec 2008 16:37:13 +0100 [thread overview]
Message-ID: <20081209163258.B7055@colin2.muc.de> (raw)
In-Reply-To: <493E7D65.3020405@foxmail.com>
On Tue, 9 Dec 2008, 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???
Try this (not tested):
(defun change-nth (liszt, n, nieuw)
(while (> n 0)
(setq liszt (cdr liszt)
n (1- n)))
(if liszt
(setcar liszt nieuw)))
--
Alan Mackenzie (Nuremberg, Germany).
next prev parent reply other threads:[~2008-12-09 15:37 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-09 14:15 How could I modify list element? richardeng
2008-12-09 15:37 ` Alan Mackenzie [this message]
2008-12-09 17:43 ` richardeng
[not found] ` <mailman.2345.1228845668.26697.help-gnu-emacs@gnu.org>
2008-12-09 20:30 ` Andreas Politz
2008-12-09 17:21 ` Thierry Volpiatto
2008-12-09 17:26 ` Thierry Volpiatto
[not found] <mailman.2319.1228836378.26697.help-gnu-emacs@gnu.org>
2008-12-09 16:36 ` Andreas Politz
2008-12-09 20:46 ` Niels Giesen
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