vl-sort help
@zph wrote:
rkmcswain,
Thank you for the reply.
Yeah, I saw the specific use of the word *may*; I raised an eyebrow. Not the most useful explanation I've ever read.
I checked out Lee Mac's functions and I did find one that was able to eliminate the duplicated dotted pair.
Thanks!
~Z
Just to remove duplicated items in a list, you can use this:
(defun distinct (lst)
(if lst
(cons (car lst) (distinct (vl-remove (car lst) lst)))
)
)
As this remains quite confusing according to how the list to be sorted have been built (as shown by @ActivistInvestor), I'd use two different and more explicit functions: one to sort and remove duplicates and another one to sort and do not remove duplicates.
(defun SortWithoutRemovingDuplicates (lst fun)
(mapcar '(lambda (x) (nth x lst)) (vl-sort-i lst fun))
)
(defun SortAndRemoveDuplicates (lst fun / distinct)
(defun distinct (lst)
(if lst
(cons (car lst) (distinct (vl-remove (car lst) lst)))
)
)
(vl-sort (distinct lst) fun)
)
@john.uhden wrote:
This might help:
(defun remdupes (old / new) (foreach item old (if (not (vl-position item new))(setq new (cons item new))) ) (reverse new) )
Command: (setq x (list "a" "d" "b" "a" "c" "d"))
("a" "d" "b" "a" "c" "d")
Command: (remdupes x)
("a" "d" "b" "c")
This reminds me a challenge at TheSwamp.
@ActivistInvestor wrote:
That was back during a time when AutoLISP's stack was too limited for recursive solutions.
(defun distinct (lst) (distinct-sub lst nil) ) (defun distinct-sub (lst dupes) (cond ( (not lst) nil) ( (vl-position (car lst) dupes) (distinct-sub (cdr lst) dupes)) (t (cons (car lst) (distinct-sub (cdr lst) (cons (car lst) dupes)))) ) )
Should not it have been:
(defun distinct (lst / distinct-sub)
(distinct-sub lst nil)
)
(defun distinct-sub (lst dupes)
(cond
( (not lst) (reverse dupes))
( (vl-position (car lst) dupes)
(distinct-sub (cdr lst) dupes))
(t (distinct-sub (cdr lst)
(cons (car lst) dupes)))
)
)
