Topic: Export coordinates of points in order

[Coder]

pts is list of xyz points... And it is written (vl-sort pts (function (lambda ...)))... But I was ab to ask why is vl-sort function dangerous to use like its written here
M.R.

I think because the name of the routine is the same as the function name . 

[ribarm]

Code: [Select]

(defun-q vl-sort (lst func)
   (mapcar
     '(lambda (x) (nth x lst))
      (vl-sort-i lst func)
   )
)

|;
;;; This will ensure that (vl-sort) does not remove
;;; elements that it sees as equal.


It seems that vl-sort is useful only if comparison is possible between each pair of elements of a list. If comparison is impossible (pair is equal by comparison values) seems that vl-sort removes one comparing element from list, I am guessing second one...

[ribarm]

Yes it removes duplicates, but I don't know witch ones...

Code: [Select]

Command: (vl-sort '((5 . 1) (9 . 3) (9 . 4) (9 . 5)) '(lambda (x y) (< (car x)
(car y))))
((5 . 1) (9 . 3) (9 . 4) (9 . 5))

Command: (vl-sort '((5 . 1) (9 . 3) (9 . 3) (9 . 3)) '(lambda (x y) (< (car x)
(car y))))
((5 . 1) (9 . 3) (9 . 3) (9 . 3))

Command: (vl-sort '(5 9 9 9 10 15) '(lambda (x y) (< x y)))
(5 9 10 15)

I can't make conclusion with these examples...