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Re: Adding Lists/Sequences
From: |
Pascal J. Bourguignon |
Subject: |
Re: Adding Lists/Sequences |
Date: |
Tue, 23 Sep 2008 21:26:19 +0200 |
User-agent: |
Gnus/5.1008 (Gnus v5.10.8) Emacs/22.2 (gnu/linux) |
Thierry Volpiatto <thierry.volpiatto@gmail.com> writes:
> Nordlöw <per.nordlow@gmail.com> writes:
>
>> Is there a general function, say foo, that adds lists or, even better,
>> sequences together?
>>
>> I want this
>> (foo '("a" "b") '("c" "d"))
>> to evaluate to
>> '("a" "b" "c" "d")
>
> ,----
> | ELISP> (nconc '("a" "b" "c") '("d" "e" "f"))
> | ("a" "b" "c" "d" "e" "f")
> `----
Very bad!
(defun bad-bad (tail)
(nconc '(a b c) tail))
(bad-bad '(1 2 3)) --> (a b c 1 2 3)
(bad-bad '(4 5 6)) --> (a b c 1 2 3 4 5 6) ; !!!
NEVER use a destructive function on literal data!
> Note: `append' is not destructive
append is much better, but be careful that it shares the tail, so you
must consider the result as a literal data, unless you have consed the
tail yourself.
--
__Pascal_Bourguignon__
- Adding Lists/Sequences, Nordlöw, 2008/09/23
- Message not available
- Re: Adding Lists/Sequences, David Kastrup, 2008/09/23
- Re: Adding Lists/Sequences, Thierry Volpiatto, 2008/09/24
- Re: Adding Lists/Sequences, Nikolaj Schumacher, 2008/09/24
- Re: Adding Lists/Sequences, Thierry Volpiatto, 2008/09/24
- RE: Adding Lists/Sequences, Drew Adams, 2008/09/24
- Re: Adding Lists/Sequences, Thierry Volpiatto, 2008/09/24
- Re: Adding Lists/Sequences, David Kastrup, 2008/09/24
- Re: Adding Lists/Sequences, Thierry Volpiatto, 2008/09/24
- RE: Adding Lists/Sequences, Drew Adams, 2008/09/24