Re: Partition for Emacs Lisp

[Vassil Nikolov]

> On Jun 28, 6:26 am, Marc Tfardy <b...@cyk.cyk> wrote:
>> ...
>> (partition '(a b c d e f) 2)
>> 
>> should return:
>> ((a b) (c d) (e f))
>> 
>> Is there something ready out from the box?

  (Define "out from the box"...)

    (when (and (fboundp 'featurep) (featurep 'emacs))  ;seen in comp.lang.lisp
      (require 'cl))

    (defun partition (l n)  ;"demo" grade, cursorily tested
      "Return a list of L's consecutive sublists of length N."
      (assert (zerop (mod (length l) n)))
      (loop for l on l by #'(lambda (l) (nthcdr n l)) collect (subseq l 0 n)))
  
    (partition '(a b c d e f) 2)
    => ((a b) (c d) (e f))

  ---Vassil.


-- 
Vassil Nikolov <vnikolov@pobox.com>

  (1) M(Gauss);
  (2) M(a) if M(b) and declared(b, M(a)),
  where M(x) := "x is a mathematician".