RetroBBS - comp.lang.lisp - .Re: Mapcar: how can I pass the list index to the function?

.Re: Mapcar: how can I pass the list index to the function?

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https://www.rocksolidbbs.com/devel/article-flat.php?id=16911&group=comp.lang.lisp#16911

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From: No_spamming@noWhere_7073.org (Robert L.)
Newsgroups: comp.lang.lisp
Subject: .Re: Mapcar: how can I pass the list index to the function?
Date: Sun, 20 Feb 2022 23:45:24 -0000 (UTC)
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by: Robert L. - Sun, 20 Feb 2022 23:45 UTC

On Feb 5, 1:56 pm, Brian Houser <brianlhou...@gmail.com> wrote:
> Hi comp.lang.lisp,
>
> I'm relatively new to common lisp, so forgive me if this should be
> obvious: Is it possible to pass the list index to the function using
> mapcar? For example:
>
> > (mapcar #'(lambda (x index) (if (oddp index) T NIL)) '(1 2 3 4))
>
> (NIL T NIL T)
>
> Thanks!
> Brian

Gauche Scheme:

(map list
(lrange 0)
'(a b c d))

===>
((0 a) (1 b) (2 c) (3 d))

Old mail has arrived.

devel / comp.lang.lisp / .Re: Mapcar: how can I pass the list index to the function?

devel / comp.lang.lisp / .Re: Mapcar: how can I pass the list index to the function?

Subject	Author
.Re: Mapcar: how can I pass the list index to the function?	Robert L.