From: Barry Margolin <barmar@alum.mit.edu>
To: help-gnu-emacs@gnu.org
Subject: Re: Setting the nth element of a list
Date: Thu, 04 Jun 2009 22:25:19 -0400 [thread overview]
Message-ID: <barmar-89F050.22251904062009@mara100-84.onlink.net> (raw)
In-Reply-To: 8a7c4d36-195d-4517-827e-7fbeca7ae03f@r34g2000vba.googlegroups.com
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In article
<8a7c4d36-195d-4517-827e-7fbeca7ae03f@r34g2000vba.googlegroups.com>,
Nordlöw <per.nordlow@gmail.com> wrote:
> This simple example changes the second element in the list x:
>
> (setq x '(a nil c))
> (setcar (cdr x 'b)
>
> How do I generalize this to a function that sets (changes) the nth
> element of a list (for side effects only)?
>
> Thanks in advance,
> Nordlöw
(require 'cl-macs)
(setf (nth n x) 'b)
--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***
next prev parent reply other threads:[~2009-06-05 2:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-04 21:08 Setting the nth element of a list Nordlöw
2009-06-04 22:06 ` Drew Adams
2009-06-04 22:35 ` Lennart Borgman
2009-06-05 2:25 ` Barry Margolin [this message]
2009-06-05 13:06 ` Nordlöw
2009-06-05 13:10 ` Nordlöw
2009-06-05 13:25 ` Pascal J. Bourguignon
2009-06-05 13:57 ` Nordlöw
2009-06-05 15:08 ` Pascal J. Bourguignon
2009-06-05 16:56 ` bigfaceworm
2009-06-06 6:01 ` Miles Bader
2009-06-05 20:51 ` Barry Margolin
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