How to return null in Arcade with Calculate Field (python works fine)?

[JimmyKnowles]

Trying to use the Calculate Field GP tool in ArcGIS Pro 2.2.3. I need to use logic (if else statements) to modify some field values.

I've searched and searched and can't find how to do this in Arcade.

In python, the following works fine. It actually sets the field to Null (verified by an isNull definition query).

return None‍‍

In Arcade, the following just returns 0

return null‍‍

I've tried a bunch of other things with Arcade, but no success.

Anyone have any ideas how to return null with Arcade?

[TL2]

Looks like its fixed in 2.5 

[TL2]

This is not fixed in 2.5 within Attribute Rules.

 BUG-000119064: Calculating a value to null using Arcade returns 0 is fixed when using the stand alone Calculate Field tool.

https://community.esri.com/thread/247788-cant-return-null-when-using-attribute-rule-editupdate-and-a... 

[BertKraan]

I came along this issue after a 'feature class to feature class' conversion altered the <null> values in one of my attributes to '0' (arcgis pro 2.6.0)

I used this calculate field expression to fix it:

iif ($feature.wijziging == 0,null,$feature.wijziging)

Not very happy about the unwanted conversion though but happy enough to find your tips here!

Have a great day Guys!

Bert

[LyonMNGIS]

Hi,

I am still having issues with null in Arcade for text fields.  Has anyone had any luck with null values for text fields?

iif (OutString == '', null, OutString);

Thanks

[AJR]

This bug also manifests itself if you try to use an arcade expression to operate on the shape and some of the shapes are null.  There doesn't seem to be any way in arcade to detect if the shape is null before attempting to use it (i.e. intersect it with another feature class).  I'm curious when/if this bug is on the timeline for getting fixed.

[Bud]

Related:

• Attribute Rules Idea: isBlankShape function (shape is null, or geometry is nil or null)
• ArcGIS Pro Idea: Conditionally skip field calculation for certain rows

[Bud]

Arcade:

Instead of checking for a null shape, can you count the vertices? If there are no vertices, then could you assume the shape is null? (or the geometry is nill or null)

Or if it is a line or polygon FC, could you check if the length is greater than 0? If I remember correctly, it's possible to check the length using an Arcade function or by referring to the Shape.Length "field". Related comment here: hasCurve Arcade geometry property.

SQL:

Is there a way to check if the shape is null using SQL (within the Arcade expression)?

Or if not, could you use a related database view that has a calculated field for flagging isNull (0 or 1)? And then use Arcade to reference the flag field in the related view?

Related:

• Attribute Rules Idea: Use a database function in an attribute rule
• Python Questions: Use a SQL expression inside a Python or Arcade field calculation?

[AJR]

There isn't an arcade function to count the number of vertices in a shape - https://developers.arcgis.com/arcade/function-reference/geometry_functions/

using Count(Text(Geometry($feature))) returns a result when used in the field calculator (null shapes are returned as empty strings), but trying to use Count(Text(Geometry($feature))) > 0 as a null shape filter fails when used as part of an attribute rule (i.e. null shapes pass the check)

[Bud]

For what it's worth, I was able to set a value to null using Arcade in the field calculator in ArcGIS Pro 3.2.2 (mobile and file geodatabases):

return null

It worked for setting the shape field to null as well (mobile and file geodatabases).