From: Joost Kremers <joostkremers@fastmail.fm>
To: steve-humphreys@gmx.com
Cc: help-gnu-emacs@gnu.org
Subject: Re: Appending to a list
Date: Sun, 13 Dec 2020 22:03:34 +0100 [thread overview]
Message-ID: <877dpljtwg.fsf@fastmail.fm> (raw)
In-Reply-To: <trinity-e1461f6e-8385-4745-a51a-4b1ba0a4f65b-1607892417691@3c-app-mailcom-bs09>
On Sun, Dec 13 2020, steve-humphreys@gmx.com wrote:
> Would appending to list like this be good?
>
> (setq bird '("Toucan" "King Fisher"))
> (setq bird (append bird ("Swift") ))
This should result in an error, because `("Swift")` isn't quoted. You'd need:
(setq bird (append bird '("Swift")))
But note that the last argument of `append` isn't copied, so it may not be a
good idea to use a literal list.
> Or does one customarily use other constructs for
> adding to a list?
`push` is what I would use:
(push "Swift" bird)
No need to use `setq` here.
`push` won't check if the element is already in the list, though. You can use
`cl-pushnew` in that case, but be sure to load the library it's in:
(require 'cl-lib)
(cl-pushnew "Swift" bird)
HTH
--
Joost Kremers
Life has its moments
next prev parent reply other threads:[~2020-12-13 21:03 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-13 20:46 Appending to a list steve-humphreys
2020-12-13 21:03 ` Joost Kremers [this message]
2020-12-13 21:30 ` Óscar Fuentes
2020-12-13 21:46 ` steve-humphreys
2020-12-13 22:37 ` Joost Kremers
2020-12-13 23:08 ` Joost Kremers
2020-12-13 22:43 ` Stefan Monnier
2020-12-13 23:25 ` steve-humphreys
2020-12-13 23:33 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-12-14 0:19 ` steve-humphreys
2020-12-14 0:37 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-12-14 2:54 ` steve-humphreys
2020-12-14 2:58 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-12-14 3:23 ` steve-humphreys
2020-12-14 4:07 ` Michael Heerdegen
2020-12-14 4:16 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-12-14 4:23 ` steve-humphreys
2020-12-14 4:50 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-12-14 5:13 ` steve-humphreys
2020-12-14 6:20 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-12-14 6:25 ` steve-humphreys
2020-12-14 5:28 ` steve-humphreys
2020-12-14 6:26 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-12-14 10:25 ` steve-humphreys
2020-12-14 5:55 ` steve-humphreys
2020-12-14 6:36 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-12-14 17:22 ` Michael Heerdegen
2020-12-14 18:25 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-12-15 0:17 ` steve-humphreys
2020-12-15 1:38 ` Emanuel Berg via Users list for the GNU Emacs text editor
2020-12-13 21:41 ` steve-humphreys
2020-12-13 23:31 ` Emanuel Berg via Users list for the GNU Emacs text editor
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