check the polyline have duplicated point

[ahyin]

I'm sure Lee wouldn't mind this:

(defun c:test (/ LM:UniqueFuzz LM:MAssoc ss i e)
 (vl-load-com)
 ;; © Lee Mac 2011

 (defun LM:UniqueFuzz-p (lst fuzz) ;Define a localized defun inside c:test
   (or (null lst) ;If lst is empty - or
       (and ;and the 2 following apply
         (not (vl-member-if ;The following is not a member of the residual of lst
                '(lambda (x) (equal x (car lst) fuzz))
;Temporary function to check equality to a fuzz of the 1st item in lst
                (cdr lst) ;The residual of lst
              )
         )
         (LM:UniqueFuzz-p (cdr lst) fuzz) ;Call this function again with the residual of the list
       )
   )
 )

 (defun LM:MAssoc (key lst / pair) ;Define a localized defun inside c:test
   (if (setq pair (assoc key lst)) ;Check if there is an assoc
     (cons (cdr pair) ;Return a new list containing the 1st assoc found, plus
           ;;The other assocs found by calling this same function with only the residual of the list
           (LM:MAssoc key (cdr (member pair lst)))
     )
   )
 )

 (if (setq ss (ssget "_X" '((0 . "LWPOLYLINE")))) ;If any LWPolies found
   (repeat (setq i (sslength ss)) ;Loop through each
     ;; Use the above 2 functions to check if the current one is unique
     (if (LM:UniqueFuzz-p (LM:MAssoc 10 (entget (setq e (ssname ss (setq i (1- i)))))) 1e-
       (ssdel e ss) ;Then remove it from the selection set
     )
   )
 )
 (sssetfirst nil ss) ;Select the resulting selection set
 (princ)
)

It uses recursion extensively ... something which you'll find a lot in lisp. I.e. a function calling itself in order form a loop. This is sometimes better / easier / more efficient than using the normal while / repeat / etc. loops. In the above case it's one of these times.

 

Also notice Lee's stepping through the list from the last entity - decrementing the i (index) variable. There's 2 reasons behind this: (1) it's slightly more efficient than the other way round; and (2) because he's removing elements from the selection set, the length changes - thus if #4 is remove, then the old #5 becomes the new #4, so incrementing i would skip some items.

 

Thanks you clearly explanation, it is more easy to understand.

[Lee Mac]

Thanks Irné, a nice explanation

[VVA]

VVA, just curious, why:

 

(mapcar '+ < .. >  '(0 0))

 

Obviously the (0 0) is not affecting the result in any way so are you using this method to ensure the return from mapcar is a 2D point?

Yes, I'm such a way to remove the coordinate z. Although more research I did not hold. Possible, list will run faster.

[JohnM]

I’m all for learning new ways to do things but why not use the overkill command?

[ahyin]

I’m all for learning new ways to do things but why not use the overkill command?

 

I try to use overkill command but a very simple drawing have the following error, I don't why ?

 

Initializing...

Initializing...

Initializing...

Initializing...Hard error occurred ***

internal stack limit reached (simulated)

[JohnM]

where you doing the whole drawing?

could you post the drawing

overkill worked for me

[ahyin]

where you doing the whole drawing?

could you post the drawing

overkill worked for me

hi Johnm

 

Please try the test.dwg

test.zip

[JohnM]

I did not receive any errors

Play with the command and see what it can do

The big object worked out ok

The 2 small ones did not because there was a zero length line at the top left point

[Lee Mac]

I try to use overkill command but a very simple drawing have the following error, I don't why ?

 

Initializing...

Initializing...

Initializing...

Initializing...Hard error occurred ***

internal stack limit reached (simulated)

 

I've seen this happen with other Express Tools LISP functions that are loaded using the acet-autoload2 function - it is usually caused by having another LISP file in the Support Path with the same filename as that of an Express Tool LISP, but with a different command syntax.

 

The same problem was experienced here.

[ahyin]

I've seen this happen with other Express Tools LISP functions that are loaded using the acet-autoload2 function - it is usually caused by having another LISP file in the Support Path with the same filename as that of an Express Tool LISP, but with a different command syntax.

 

The same problem was experienced here.

 

Thank you ! I have already register, and I will check it later.

Lee Mac can you give me a hand, I want draw the polylines again on top of existing polyline by "bpoly "command based on the your selected result. How to write is code ? Thank you very much !