topic Re: Unable to return distinct count in Arcade data expression in ArcGIS Dashboards Questions

Unable to return distinct count in Arcade data expression

ZenMasterZeke — Wed, 08 Mar 2023 15:48:58 GMT

I have an Arcade data expression I'm trying to set as the source for an indicator widget in a dashboard on our Enterprise Portal. This expression should return a count of distinct sites in a hosted feature layer, e.g. 5 distinct sites from 684 records.

The expression below works in the expression editor, returning a Number type of 5, but the Source tab shows an error icon with the message 'Unable to execute Arcade expression'. It seems like this should be a relatively simple expression. All clues and help appreciated, thanks.

Credit to @jcarlson, expression based on answer here.

var ptl = Portal('https://portal_url/') var fs = FeatureSetByPortalItem( ptl, 'itemid', 0, ['site'], false ); return Count(Distinct(fs, 'site'))

Re: Unable to return distinct count in Arcade data expression

jcarlson — Wed, 08 Mar 2023 16:52:18 GMT

Data expressions need to return a FeatureSet. The Indicator can handle the Count portion, so just return Distinct(fs, 'site'), then configure the widget.

Re: Unable to return distinct count in Arcade data expression

ZenMasterZeke — Wed, 08 Mar 2023 17:51:10 GMT

Thanks! Works great. Don't know why it worked in the expression editor but not elsewhere, but good enough.

Re: Unable to return distinct count in Arcade data expression

jcarlson — Wed, 08 Mar 2023 18:37:09 GMT

Well, the expression editor will return anything so long as the expression is valid. You could have the expression Boolean() and it would return a value. It's when the expression is being loaded by the Dashboard that it looks for the FeatureSet.

Similarly, the Popup editor will return a FeatureSet, but when the popup evaluates the expression, it's looking for something it can render as text or HTML, and a FeatureSet will just show up as [Object object] or something.