unofficial mirror of help-gnu-emacs@gnu.org
 help / color / mirror / Atom feed
* How to mapcar or across a list?
@ 2015-07-15 20:14 Marcin Borkowski
  2015-07-15 20:42 ` Rasmus
                   ` (3 more replies)
  0 siblings, 4 replies; 21+ messages in thread
From: Marcin Borkowski @ 2015-07-15 20:14 UTC (permalink / raw)
  To: Help Gnu Emacs mailing list

Hi there,

so here's my problem: I have a list of Boolean values, and I want to
`mapcar' an `or' across it (IOW, I want to test whether at least one of
them is true).  Of course, (apply #'or my-list) does not work.  Of
course, I can (cl-reduce (lambda (x y) (or x y)) my-list) -- but is
there a better method?

BTW, my-list doesn't really exist: it is a result of `mapcar'ing
a function taking some value and yielding a Boolean value, so bonus
points if the method does not process the whole list.

(Note: I just noticed that my-list is in fact sorted so that all true
values (if any) will occur at the beginning anyway, so I can just test
the first one.  This means that my problem is purely academic, though
still interesting, I guess.)

Best,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University



^ permalink raw reply	[flat|nested] 21+ messages in thread

end of thread, other threads:[~2015-07-17  8:55 UTC | newest]

Thread overview: 21+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-07-15 20:14 How to mapcar or across a list? Marcin Borkowski
2015-07-15 20:42 ` Rasmus
2015-07-15 20:55   ` Marcin Borkowski
2015-07-15 22:21 ` Emanuel Berg
2015-07-15 22:21 ` John Mastro
     [not found] ` <mailman.6977.1436998965.904.help-gnu-emacs@gnu.org>
2015-07-15 22:28   ` Pascal J. Bourguignon
2015-07-15 22:36     ` Emanuel Berg
2015-07-15 22:57     ` never use `eval' (was: Re: How to mapcar or across a list?) Emanuel Berg
2015-07-15 23:27       ` John Mastro
2015-07-15 23:57         ` Emanuel Berg
2015-07-16  0:18           ` John Mastro
     [not found]         ` <mailman.6984.1437004760.904.help-gnu-emacs@gnu.org>
2015-07-16  0:04           ` Barry Margolin
     [not found]     ` <mailman.6982.1437001117.904.help-gnu-emacs@gnu.org>
2015-07-16  0:01       ` Barry Margolin
2015-07-16  1:13         ` Emanuel Berg
2015-07-17  0:55           ` Emanuel Berg
     [not found]           ` <mailman.7027.1437094623.904.help-gnu-emacs@gnu.org>
2015-07-17  1:39             ` never use `eval' Pascal J. Bourguignon
2015-07-17  2:16               ` Emanuel Berg
2015-07-17  8:36               ` Barry Margolin
2015-07-17  8:55                 ` Pascal J. Bourguignon
2015-07-16  0:22       ` Pascal J. Bourguignon
2015-07-16  1:11         ` Emanuel Berg

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).