Sort SS based on creation order

Does anyone know a way to take a list of object handles and sort them by
their HEX value?

The final list would be then sorted from oldest to newest object.

Thanks,

Don

 

Hi Don

AFAIK a selection set reflects the creation order...

Cheers

 

Except when you manually select the objects, or use more than 1
window/crossing.....

and even if you do select them by window, crossing or All, the order is
reversed.....first item in ss is the last one created.

Jeff

 

I'm very sorry, but I forgot to update the message header after I changed
the body of the message.

I am trying to sort a list of entity handles.

1. Select objects
2. Extract handles into a list.
3. Sort the list from lowest number to highest number based on handle
value.
4. Create new SS and SSADD each entity in correct order.

Another option is to bypass creating a new SS and modify the selected
objects based only on the sorted list.

I assume the key is to convert the handle to a number that can be sorted.

Thanks,

Don

 

Seems that (acad_strlsort) can handle the sorting.

 

Maybe I'm wrong, but couldn't you just do:
(setq ss (ssget "X"))
and sift through each entity, make a 'list' of the handles,
then merely 'reverse' the list ?

Bob

 

What I'm trying to do is...

The user places callout tags programmatically for a bill of materials.

Later he numbers the tags in a logical sequence to coincide with the order
of fabrication.

I want to also give him the option to quickly number the tags in the order
the tags were created.

He would window the tags and they would be numbered thusly.

Don

 

Are all handles able to be sorted this way regardless of the size of the
drawing?

Would they indicate the order of creation?

Seem pretty simple.

Thanks,

Don

 

I can't think of anything that would indicate
otherwise. Someone please correct me if
I am wrong

 

So I guess Handles can always be sorted based on their interpreted values
via VL-SORT-I.

I'm sorry I'm so dense at this. I don't know anything about HEX
representations.

I appreciate your help.

Don

 

Wow, that would be too easy! I'm going to experiment.

Thanks,

Don

 

Yes, I've tried too. Amazingly simple.

Don

 

wE cAn't bE tHaT CrItiCaL !



Don

 

You can't use VL-SORT to sort entity handles this way.

See if you can figure out why.



AutoCAD based Security Planning Solutions:
http://www.caddzone.com/securityplanning

 

It is my understanding that the entity handles are being reused by acad.
the order of handless DOES NOT represent the order of creation. I do
remember this from one of your posts, Tony. I just can't remember more
details about it. Bottom line for me is that handles do not represent
the history!

Viliam

 

Viliam - The reason you can't sort handles without some
extra work, is because handles are returned as strings,
which means that they're treated as strings by the >
or < functions:

"FF" = 255

"AAA" = 2730

Command: (> "AAA" "FF")
nil

Since not all handles have the same string width, or
number of hexadecimal digits, the strings must be
left-padded with 0's or spaces, or it is not a numeric
comparision.

 

Excellent points.

If the handles are not reused (I doubt they are),
it might be possible to use

;;Conversion from hexadecimal to decimal
;;Assumes hexadecimal notation is upper case.
;;Returns real decimal number
(defun Hex2Dec (str / sum)
;;D.C.Broad
(setq sum 0)
(foreach n (vl-string->list str)
(setq n (IF (< n 65) (- n 48)(- n 55)))
(setq sum (+ n (* sum 16.0))))
sum)

(vl-sort-i (mapcar 'hex2dec handlelist) '<)

to get an indexed list of the correct entity order.

Of course it might be easier to just parse the
entities in the drawing with entnext and see
if its associated handle is in the list.

 

Thanks for the link.

Don

 

Tony,

Two questions...

1. Do you know if entity handles are ever re-used? I.E. an entity was
deleted from the drawing database.
2. Do they represent the sequential order of creation? If not, is there
another way to determine the order?

It was my understanding that 1=NO and 2=YES

Thanks

Don

 

Thanks Doug

Don