Lisp: how to select all circles inside a polygon

I'd like to know a code in LISP for selecting all circles inside a polygon I made and center them in the centre of the same polygon.

Try this and let me know .

(defun c:Test (/ s sn l i d lst p a b j k ss)
 ;;    Tharwat 15. may. 2014        ;;
 (princ "\n Select a 2Dpolyline ...")
 (if (setq s (ssget "_+.:S:E" '((0 . "LWPOLYLINE"))))
   (progn (setq l (vlax-curve-getdistatparam (setq sn (ssname s 0)) (fix (vlax-curve-getendparam sn)))
                i (/ l 1000.)
                d i
          )
          (repeat 1000
            (setq lst (cons (vlax-curve-getpointatdist sn i) lst)
                  i   (+ i d)
            )
          )
          (setq p (mapcar 'cdr (vl-remove-if-not '(lambda (x) (eq (car x) 10)) (entget sn)))
                a (mapcar 'car p)
                b (mapcar 'cadr p)
                j (/ (apply '+ a) (length a))
                k (/ (apply '+ b) (length b))
          )
          (if (setq ss (ssget "_CP" lst '((0 . "CIRCLE"))))
            ((lambda (x / n e)
               (while (setq n (ssname ss (setq x (1+ x))))
                 (if (vlax-write-enabled-p (vlax-ename->vla-object n))
                   (entmod (subst (cons 10 (list j k 0.)) (assoc 10 (setq e (entget n))) e))
                 )
               )
             )
              -1
            )
          )
   )
 )
 (princ)
)(vl-load-com)

works great thank you but can you write after each code line what you did there so i can understand it?

You're welcome .

It is hard to explain everything in the routine but if you have any specific question , I can explain it for you .

Well i cant really understand much, i was thinking to say like

: here you check if the centre of circle is in polygon

; here you move the centre to the centre of polygon ...

a few comentaries would make the understanding of the code way more easy

also the meaning of each charater: s sn l i d lst p a b j k ss

What are they

Okay ,

First we select a polyline then write the codes to make a list of point along the selected polyline so after that we can a selection set with the help with these point to select only circle as shown in the feed code for the ssget function , so if circles found we get the centeriod point of the polyline then update the center of each circle to that point .

That's it

also the meaning of each charater: s sn l i d lst p a b j k ss

What are they

These called local variables .

yeah i'd like to know which each local variable means....

yeah i'd like to know which each local variable means....

Read THIS about variables .

i know about variables per general. I mean in my program what is "s"-> the polygon i select

and so on

i know about variables per general. I mean in my program what is "s"-> the polygon i select

and so on

the 's' variable holds the selection set of the polyline , so I could have wrote it like this : sel or myselect ... etc as best as the programmer wants .

well exactly that i want to know, each and every variable:

s-> variable holds the selection set of the polyline

sn->

l ->

d->

lst->

p->

a->

b->

j->

k->

ss->

If you could tell me it would help me alot

circles where drawn from a base point i suppose etc ect.

Now that must be the center of all of them i hope now a polyne was drawn from a point also so the center points must be moved over the next one along with in this case the circles.

I hope a lisp is not needed to have click on the mouse button and move things around if so i am anxious to see it and perhaps it should be built with a voice command imagine how operating cad on voice command would be but the op would be yapping all day long in front of the of the screen.