Compare 2 objects

How compare 2 obj ?

if the same ,return T ,

not same , return nil

Since every object has a unique handle property, strictly speaking, identical objects do no exist...

 

1. First compare the objectname property of the two objects. If they have the same object name:
   
2. Use the atoms-family function to get a list of all functions. Filter for "vla-get-*" functions and compile a list of all properties (skip the handle property).
   
3. Check which properties are available (vlax-property-available-p) for the objects and compare values. Perhaps use vl-every to do so efficiently.
   

Like Roy_043 some of the obvious line,arc,circle,pline layer, length,area you need to provide more information about what you are comparing, solids are different again.

I Know ,

(equal e1 e2)

In its simplest, most primitive, form the function could look like this:

; (CompareEntities_P (car (entsel)) (car (entsel)))
(defun CompareEntities_P (enm1 enm2 / elst1 elst2)
 (setq elst1 (entget enm1))
 (setq elst2 (entget enm2))
 (and
   (= (length elst1) (length elst2))
   (vl-every
     '(lambda (sub1 sub2)
       (cond
         ((/= (car sub1) (car sub2))
           nil
         )
         ((vl-position (car sub1) '(-1 5)) ; Skip ename and handle.
           T
         )
         (T
           (equal sub1 sub2 1e-
         )
       )
     )
     elst1
     elst2
   )
 )
)

This example may offer some ideas - the example demonstrates a possible method of selecting blocks with similar geometry, but the idea could be translated to primary objects.

@Lee:

Interesting solution, but with a chance of false positives.

@Lee:

Interesting solution, but with a chance of false positives.

 

Thanks Roy, though a stricter comparison may miss valid results - this form of function is notoriously ambiguous.

In its simplest, most primitive, form the function could look like this:

; (CompareEntities_P (car (entsel)) (car (entsel)))
(defun CompareEntities_P (enm1 enm2 / elst1 elst2)
 (setq elst1 (entget enm1))
 (setq elst2 (entget enm2))
 (and
   (= (length elst1) (length elst2))
   (vl-every
     '(lambda (sub1 sub2)
       (cond
         ((/= (car sub1) (car sub2))
           nil
         )
         ((vl-position (car sub1) '(-1 5)) ; Skip ename and handle.
           T
         )
         (T
           (equal sub1 sub2 1e-
         )
       )
     )
     elst1
     elst2
   )
 )
)

 

Thank you Roy,