Text string to a field IF/THEN condition

[PauloMiranda8553]

I need some help here, I'm trying to set a text string to a field that read a 2 characters from the file name. Kinda of read characters 12 and 13, and if content is RD, the value should be RED, if YL, Yellow, GR - Green, and so on. I have 5 or 6 possible values.

The file name is like: X-25-034-A-PE-PGR-.dwg

I alread set this, but always get a  "$(IF,??) " error:
$(IF,$(=$(substr,$(getvar,dwgname),12,2)RD),"RED")

The IF/THEN is correct?

Can a text string be assigned to the field? Is this the way?

Help will be very apreciated.

Thanks to all.

Paulo Miranda

[Brock_Olly]

From chatGPT:

You're on the right track, but the issue comes from how the string comparison is done in AutoCAD fields. The $(IF) function expects a specific format, and the way you're trying to compare the substring isn't quite right.

Here's an improved version of your field expression:

$(IF,$(=,$(substr,$(getvar,dwgname),12,2),RD),RED, $(IF,$(=,$(substr,$(getvar,dwgname),12,2),YL),Yellow, $(IF,$(=,$(substr,$(getvar,dwgname),12,2),GR),Green, Other)))

Explanation:

• $(substr,$(getvar,dwgname),12,2) gets the substring starting from the 12th character and extracts 2 characters.
• $(=, ...) compares the extracted substring to a specific value (e.g., RD, YL, GR).
• $(IF, ...) checks if the condition is true. If it is, it returns the first value (e.g., RED). If it's false, it checks the next condition.
• I've added an Other value at the end for any unmatched cases.

This expression should work, provided the file name is correct and consistent with your pattern. It will check for RD, YL, and GR, and return the corresponding color name.

[PauloMiranda8553]

Thanks for your reply.

The expression don't work, keep the same "$(IF,??) " error.
Now there's something I found... if I replace alphabetic (e.g., RED) for a numeric value (e.g., 01), it works...
So, the problem is there... extracted substring alphabetic/numeric comparation...

Any clue?

[paullimapa]

Make any difference if surround the characters with quotes?

$(IF,$(=,$(substr,$(getvar,dwgname),12,2),"RD"),"RED")

[Brock_Olly]

If Pauls doesn't work, does this work?

$(IF,$(=,$(substr,$(getvar,dwgname),12,2),RD),"RED",$(IF,$(=,$(substr,$(getvar,dwgname),12,2),YL),"Yellow",$(IF,$(=,$(substr,$(getvar,dwgname),12,2),GR),"Green","Other"))))

[PauloMiranda8553]

Nope... 😢😢

[PauloMiranda8553]

No, either way...

So strange...

[Brock_Olly]

Workaround Approach

1. Create a field to extract the substring (store it in a hidden attribute or text field):

   $(substr,$(getvar,dwgname),12,2)

   • This extracts the 12th and 13th characters from the drawing name.

2. Reference that extracted value in a second field for conditional logic:

   $(IF,$(=,$(substr,$(getvar,dwgname),12,2),"RD"),"RED",
   $(IF,$(=,$(substr,$(getvar,dwgname),12,2),"YL"),"YELLOW",
   $(IF,$(=,$(substr,$(getvar,dwgname),12,2),"GR"),"GREEN","OTHER"))))

   • Important: Ensure that "RD", "YL", and "GR" are explicitly treated as strings.
   • If AutoCAD still refuses to recognize it, try inserting the substring field into an attribute or MTEXT first, then referencing it in the condition.

[Brock_Olly]

I'm kind of going in the dark here so if you could upload your DWG or a sample with the field so we can test it out too that'd be nice.

[PauloMiranda8553]

Thank you  my friends, nothing work.
I attached my sample...

The field should read from the file name... but only in the numeric characteres it work.
Thanks.

[paullimapa · Accepted solution]

I wonder perhaps the problem is with using = since that’s for number comparisons. Maybe try eq instead since that’s for string comparisons 

https://help.autodesk.com/view/ACDLT/2025/ENU/?guid=GUID-F94A885A-4DA2-432B-AC1A-EB49CC6C1C72

[PauloMiranda8553]

That's the problem...
You made it.
Thank you very much... Appreciate that.

[paullimapa]

It was a group effort…cheers!!!