topic Change display field expression using ArcPy in Python Questions

Change display field expression using ArcPy

CarstenAndersson — Thu, 18 Feb 2021 11:55:21 GMT

How do I change the display field expression using ArcPy?

Re: Change display field expression using ArcPy

DanPatterson — Thu, 18 Feb 2021 12:57:17 GMT

It isn't supported in arcpy.

There are old threads to this effect

How does ArcMap decide which field is used for the... - GeoNet, The Esri Community

It isn't under arcpy's layer properties or the recent addition of CIM

Python CIM access—ArcGIS Pro | Documentation

I couldn't even find it as an Idea

Re: Change display field expression using ArcPy

CarstenAndersson — Thu, 18 Feb 2021 13:31:57 GMT

Hi Dan.

Yeah, I also tried using CIM by setting the displayField property to the required expression. It actually sets it, but it looks strange and doesn't work.

I used this Py code:

lyr_def = lyr.getDefinition("V2")
lyr_def.featureTable.displayField = "\"Matr. nr. \"+$feature.MatrikelNr+\" \"+$feature.LandsEjerlav+\" (\"+$feature.LandsEjerlavKode+\")\""

Which changes it

But for some reason it's adding a $feature. in front of my express. So no luck there. Hopefully this will be added as a possibility in the future.

Thanks for the reply 🙂

Re: Change display field expression using ArcPy

DanPatterson — Thu, 18 Feb 2021 13:46:55 GMT

$feature .... looks like Arcade to me

Re: Change display field expression using ArcPy

JoshuaBixby — Thu, 18 Feb 2021 15:29:19 GMT

displayField and displayExpressionInfo are mutually exclusive, i.e., use displayField for displaying a field only and use displayExpressionInfo for displaying an expression. You are passing an expression into displayField, which is why the "$feature" is being prepended.

Re: Change display field expression using ArcPy

CarstenAndersson — Fri, 19 Feb 2021 14:06:41 GMT

Thanks a lot, Joshua! That actual worked. I ended up with the following code:

lyr_def = lyr.getDefinition("V2")
exp_info = arcpy.cim.CIMExpressionInfo()
exp_info.expression = "\"Matr. nr. \"+$feature.MatrikelNr+\" \"+$feature.LandsEjerlav+\" (\"+$feature.LandsEjerlavKode+\")\""
lyr_def.featureTable.displayExpressionInfo = exp_info
lyr.setDefinition(lyr_def)

I really appreciate the help 🙂

Re: Change display field expression using ArcPy

DAVIDWADSWORTH_LVVWD — Mon, 26 Feb 2024 14:55:42 GMT

Thanks for raising this question, and sharing your solution. I was working with this same issue and this has saved a lot of time.

Re: Change display field expression using ArcPy

DAVIDWADSWORTH_LVVWD — Mon, 26 Feb 2024 15:17:53 GMT

Thanks for contributing to this solution. I had the same question and you have saved me a lot of time.