# Looking for a function that could do that

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```(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 ?

Thanks

Patrick

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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 ?

Thanks

Patrick

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

hth

ole

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`(matrix-transpose '((1 2 3) (a b c) (4 5 6)))`

Thank you

Patrick

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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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`(apply #'mapcar #'(lambda (&rest all) all) lists))`

this is really cool! :-)

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`(apply #'mapcar #'list '((1 3 5) (2 4 6)))`

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Thank you to all of you for your time and your help

Patrick

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