rotten news relay - comp.lang.lisp - Re: cloning elements in a list

Subject: Re: cloning elements in a list
From: B. Pym
Newsgroups: comp.lang.lisp
Organization: A noiseless patient Spider
Date: Mon, 2 Sep 2024 03:39 UTC

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From: Nobody447095@here-nor-there.org (B. Pym)
Newsgroups: comp.lang.lisp
Subject: Re: cloning elements in a list
Date: Mon, 2 Sep 2024 03:39:39 -0000 (UTC)
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> > How to write a lisp function which clones the top-level elements of a list
> L
> > (first arguement) n ( second argument) times. for eg. (clone 'A B C) 4 )
> > produces ( AAAABBBBCCCC)
>
> To rewrite your question to what I *think* you mean:
> (clone '(A B C) 4 )
> => (A A A A B B B B C C C C)
>
> try this:
> CL-USER 143 > (defun stretch (list factor)
> (loop for elt in list
> nconc (make-list factor :initial-element elt)))
> STRETCH
>
> CL-USER 144 > (stretch '(a b c) 4)
> (A A A A B B B B C C C C)

Gauche Scheme

(define (stretch lst factor)
(append-map
(cut make-list factor <>)
lst))

(stretch '(a b c) 3)
===>
(a a a b b b c c c)

Subject	Author
Re: cloning elements in a list	B. Pym

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