Sujet : Re: cloning elements in a list
De : Nobody447095 (at) *nospam* here-nor-there.org (B. Pym)
Groupes : comp.lang.lispDate : 02. Sep 2024, 05:39:39
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <vb3c1p$1r6la$1@dont-email.me>
User-Agent : XanaNews/1.18.1.6
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)