Please Help: ASSOC Polyline

[barristann]

Hi all. The below is a "print elist" of a Polyline

 

((-1 . <Entity name: 21c26e35e70>) (0 . "LWPOLYLINE") (330 . <Entity name: 21c214e69f0>) (5 . "9077") (100 . "AcDbEntity") (67 . 0) (410 . "Model") (8 . "TEXT") (62 . 1) (6 . "ByBlock") (100 . "AcDbPolyline") (90 . 2) (70 . 0) (43 . 0.1) (38 . 0.0) (39 . 0.0) (10 378.655 321.399) (40 . 0.1) (41 . 0.1) (42 . 0.0) (91 . 0) (10 367.655 340.599) (40 . 0.1) (41 . 0.1) (42 . 0.0) (91 . 0) (210 0.0 0.0 1.0)) ((-1 . <Entity name: 21c26e35e70>) (0 . "LWPOLYLINE") (330 . <Entity name: 21c214e69f0>) (5 . "9077") (100 . "AcDbEntity") (67 . 0) (410 . "Model") (8 . "TEXT") (62 . 1) (6 . "ByBlock") (100 . "AcDbPolyline") (90 . 2) (70 . 0) (43 . 0.1) (38 . 0.0) (39 . 0.0) (10 378.655 321.399) (40 . 0.1) (41 . 0.1) (42 . 0.0) (91 . 0) (10 367.655 340.599) (40 . 0.1) (41 . 0.1) (42 . 0.0) (91 . 0) (210 0.0 0.0 1.0))

 

There are 2 possible assoc 10 results.

 

I want pt = 378.655 321.399 with the bellow codes:

 

(if (setq ss (ssget ":L"))
(progn 
(setq x 0)

(setq ename (ssname ss x))
(setq elist (entget ename))
(setq pt (cdr(assoc 10 elist))) 
) ;; progn
) ;; if

 

But, these codes keeps giving me pt = 367.655 340.599 instead

 

How do I specify that I want the second assoc 10?

 

Thank you

Edited January 8 by barristann

[pkenewell]

@barristann A simple function commonly called MASSOC, which returns a list of all DXF codes of a certain prefix. There ae several variations of this function out there.

 

(defun Massoc (el dxf)
   (vl-remove-if 'null
      (mapcar (function (lambda (x)(if (= (car x) dxf) x nil))) el)
   )
)

;;Example that will return the 2nd vertex of a selected polyline.
(cdr (cadr (Massoc (entget (car (entsel))) 10)))

 

[BIGAL]

This is what I use to get a list of pline points. I think I got it from Lee-mac.

 

(setq plent (entsel "\nPick pline "))
(if plent (setq co-ord (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) (entget (car plent))))))

 

For any point use (nth x co-ord) note 1st point x=0, so for 2 points only x=1

[Steven P]

and third option, if the polyline only has 2 points on it, can try reverse, look at it 'backwards'

 

(if (setq ss (ssget ":L"))
(progn 
(setq x 0)

(setq ename (ssname ss x))
(setq elist (entget ename))
(setq pt (cdr(assoc 10 (reverse elist)))) 
) ;; progn
) ;; if

 

[barristann]

Thank you pkenewell, BIGAL, and Steven P. All of these methods work. These lessons are invaluable to me!