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Looking for a function that could do that

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46 minutes ago, rndrnd said:

(trans  '((1 2 3) (a b c) (4 5 6))


=> ((1 a 4) (2 b 5) (3 c 6))


is it somewhere in Opusmodus ? Any idea how to make it ?






(loop for x in  '(1 2 3)
  	 for y in '(a b c)
     for z in '(4 5 6)
     collect (list x y z))




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;;; in "pure lisp" with NIL when lists have not the same length

(defun trans* (lists)
  (loop repeat (car (last (sort-asc (mapcar 'length lists))))
    for cnt = 0 then (incf cnt)
    collect (loop for i in lists
                collect (nth cnt i))))
(trans* '((1 2 3 4) (a b c d) (11 12 13 14) (k l m n)))
(trans* '((1 2 3 4) (a b c d e) (11 12 13 14 14 16) (k l m n o p q r s t)))
(trans* '((1 2 3 4) (a b c d e) (11 12 13 14) (k l m n r s t)))


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Here is another approach to implement the same thing, but a but more concisely in just one line (most of the code below is the documentation :)

(defun mat-trans (lists)
  "Matrix transformation.
   (mat-trans '((a1 a2 a3) (b1 b2 b3) (c1 c2 c3) ...))
   => ((a1 b1 c1 ...) (a2 b2 c2 ...) (a3 b3 c3 ...))"
  (apply #'mapcar #'(lambda (&rest all) all) lists))


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