topic Re: Pro Arcade Expression using When in ArcGIS Pro Questions

Pro Arcade Expression using When

MichaelVolz — Mon, 02 Apr 2018 15:52:48 GMT

I am trying to calculate a field in Pro based off another field using the When function in Arcade. The field I am calculating off (TYPE) is numeric with values such as 1,2,3,4. The field I am calculating is text.

I use Calculate field and select Arcade for Expression Type and add the following text:

var type = $feature.TYPE;
When([type = 1, 'Primary', type = 2, 'Secondary', type = 3, 'Tertiary'], 'N/A')

Unfortunately, when I verify the expression I get the following error message

"Invalid Expression

Error 0 on line 2.

Close square brace expected."

I thought I was following the sample in the documentation, so I'm confused that I would get an error.

Any help to solve this issue is greatly appreciated.

Re: Pro Arcade Expression using When

DanPatterson_Retired — Mon, 02 Apr 2018 15:57:23 GMT

When(density < 50, 'low', density >=50 && density < 100, 'medium', density >= 100, 'high', 'n/a');

from here

https://developers.arcgis.com/arcade/function-reference/logical_functions/

I think the square braces was being taken too literally in your expression

Re: Pro Arcade Expression using When

MichaelVolz — Mon, 02 Apr 2018 16:18:52 GMT

That is the documentation I was reading when attempting to use the When expression. I thought I would be able to use = in my expression as the documentation does not indicate you cannot use =, but that seems to be the problem.

When I changed my syntax to:

When(type < 2, 'Primary', type > 1 && type< 3, 'Secondary', type > 2, 'Tertiary', 'N/A')

I was able to verify the expression and successfully calculate the field.

If I was to use the square braces in my expression I get an error, so the documentation seems misleading in that regard.

Re: Pro Arcade Expression using When

BalajiVeera — Mon, 02 Apr 2018 16:23:14 GMT

Use this:

var $feature.TYPE;
When(type == 1, 'Primary', type == 2, 'Secondary', type == 3, 'Tertiary', 'N/A')

Re: Pro Arcade Expression using When

DanPatterson_Retired — Mon, 02 Apr 2018 16:31:45 GMT

I think the square brackets are referring to a list of optional parameters, not an actual list