Points of leader

(setq pt(nentsel (strcat "\n Select a leader  < exit > : ")));get entity
(setq e (entget (car pt)));;association list of entity
(setq p1 (assoc 10 e))

How can I get 3 points of leader.

Use the lisp function MEMBER It searches a list for an occurrence of an expression and returns the remainder of the list, starting with the first occurrence of the expression so:

(defun C:test (/ e pt p2 p3)
(setq pt(nentsel (strcat "\n Select a leader  < exit > : "))
      e (entget (car pt));;association list of entity
      e (member (assoc 10 e) e)
      p1 (cdr (assoc 10 e));; cdr removes the 10 leaving the coordinates.
      e (cdr e)
      p2 (cdr (assoc 10 e))
      e (cdr e)
      p3 (cdr (assoc 10 e))
)
       (princ "\np1=")(princ p1)(princ ", p2=")(princ p2)(princ ", p3=")(princ p3)(princ)
)

should return what you're looking for.

You may want to search for qlset.lsp by Frank Whaley who worked for Autodesk. This code allows you to examine the current QLEADER settings, or to initialize the setting before using the QLEADER command. It can tell you how many points the leader has for example. Not everyone uses the default settings.

First define a function that will check for that group code key, and return its value:

(defun IsItDxf10 ( x )
 (if (= (car x) 10) (cdr x))
)

Second learn how to use vl-remove-if-not function to retrieve the items from the list that match the function's criteria.

Assuming that you know the dxf elist is obtained via (entget ).

Use a method similar to that which I describe here.

Thanks all fore helping me.

Now I need to feed new value to third point of the leader. How can do that. Pl.help

Now I need to feed new value to third point of the leader. How can do that. Pl.help

You could use a function similar to the following:

(defun substnthkey ( idx key val lst / cnt )
   (setq cnt -1)
   (mapcar
       (function
           (lambda ( itm )
               (cond
                   (   (/= key (car itm)) itm)
                   (   (/= idx (setq cnt (1+ cnt))) itm)
                   (   (cons key val))
               )
           )
       )
       lst
   )
)

Example:

_$ (substnthkey 1 10 '(0 0 0) '((1 . "A") (2 . "B") (10 1 2 3) (3 . "C") (10 2 3 4) (4 . "D") (10 3 4 5)))
((1 . "A") (2 . "B") (10 1 2 3) (3 . "C") (10 0 0 0) (4 . "D") (10 3 4 5))

This could also be written recursively:

(defun substnthkey-rec ( idx key val lst )
   (cond
       (   (null lst) nil)
       (   (or (/= key (caar lst)) (< -1 (setq idx (1- idx))))
           (cons (car lst) (substnthkey-rec idx key val (cdr lst)))
       )
       (   (cons (cons key val) (cdr lst)))
   )
)

Thumbs up, Lee!

Thanks Grrr

Thanks Mr Lee Mac