Am I using the ssget Relational Operators (filters) correctly?

[aridzv]

Hi.

I want to select:

lwpolylines

4 vertices

layer "Layout_Frame"

DXF code 70 greater then "0".

 

I want to use (-4 . ">") to get lwploylines with DXF code 70 greater than "0".

 

can I use the code this way (as with "OR" & "AND"):

(ssget '((0 . "LWPOLYLINE") (90 . 4) (8 . "Layout_Frame") (-4 . ">") (70 . 0)))

 

or should I "close" the (-4 . ">") this way:

(ssget '((0 . "LWPOLYLINE") (90 . 4) (8 . "Layout_Frame") (-4 . ">") (70 . 0) (-4 . ">")))

 

 

thanks,

aridzv.

Edited April 27 by aridzv

[marko_ribar]

If you want to select LWPOLYLINE entities that are closed (not DXF70 = 0/128), I'd suggest something like this...

(ssget (list (cons 0 "LWPOLYLINE") (cons 90 4) (cons 8 "Layout_Frame") (cons -4 "<or") (cons 70 1) (cons 70 129) (cons -4 "or>")))

Or just little simplyfied...

(ssget (list (cons 0 "LWPOLYLINE") (cons 90 4) (cons 8 "Layout_Frame") (cons -4 "&=") (cons 70 1)))

 

[aridzv]

thanks @marko_ribar

 

I use this (which is your first line actually...):

(ssget '((0 . "LWPOLYLINE") (90 . 4) (8 . "Layout_Frame") (-4 . "<OR") (70 . 1) (70 . 129) (-4 . "OR>")))

 

I have tow questions:

1. when using (-4 . ">") when the condition stop,

or is it refering just to the first DXF code that is next to it ?

 

2.  how this code:

(cons -4 "&=") (cons 70 1)

 

get both (70 . 1) and (70 . 129)?

What does "&=" sign do to make it different from just "=" ?

thanks,

aridzv.

Edited April 27 by aridzv

[Lee Mac]

DXF group 70 always holds a bit-coded integer value (i.e. an integer for which each bit (power of 2) encodes a setting); given this, you should use the bitwise relational operators ("&" and "&=") when filtering bit coded values.

 

Here:

• The "&" operator is equivalent to the AutoLISP expression  (/= 0 (logand bit filter)) and means all of the filter bits must be set.
• The "&=" operator is equivalent to the AutoLISP expression (= filter (logand bit filter)) and means any of the filter bits can be set.

For your example, you state:

Quote

DXF code 70 greater then [sic] "0".

 

This implies that you want to select either closed polylines, or polylines with linetype generation enabled, or both - and so the filter would be:

(ssget "_X" '((0 . "LWPOLYLINE") (-4 . "&") (70 . 129)))

If instead, you mean to select only closed polylines, you should use:

(ssget "_X" '((0 . "LWPOLYLINE") (-4 . "&=") (70 . 1)))

 

Edited April 27 by Lee Mac

[aridzv]

Hi @Lee Mac and thanks for the reply.

 

in this case I wanted to select closed polylines regardless of thier linetype generation conditions.

when I used:

(ssget '((0 . "LWPOLYLINE") (90 . 4) (8 . "Layout_Frame") (70 . 1)))

 

it ommited lwpolylines that was closed and had thier  linetype generation enabled => (70 . 129).

Edited April 27 by aridzv

[aridzv]

other question is about the use of (-4 . ">").

dose it refer only to the elemnt next to it or will it refer to all the elements after it?

[Lee Mac]

4 hours ago, aridzv said:

Hi @Lee Mac and thanks for the reply.

 

in this case I wanted to select closed polylines regardless of thier linetype generation conditions.

when I used:

(ssget '((0 . "LWPOLYLINE") (90 . 4) (8 . "Layout_Frame") (70 . 1)))

 

it ommited lwpolylines that was closed and had thier  linetype generation enabled => (70 . 129).

 

You should use the bitwise equals operator ("&="), as I have explained above.

[GLAVCVS]

Regarding your question about additional filters after (-4 . ">")
The answer is that you must repeat the filter (-4 . ">") as many times as necessary to achieve the expected result.
For example:
.... (-4 . ">") (62 . 1) (90 . 3)... will not return the expected result.
But... (-4 . ">") (62 . 1) (-4 . ">") (90 . 3)... YES

This is true at least in AutoCAD. I don't know if this works the same way in BricsCAD.

Edited April 28 by GLAVCVS