Why is there a limit to the number of attributes with an expression in styles?

Question

I'm working with census data, and I need to add an expression to a style so I can show the left-over total population from the population attributes.  If there are three attributes chosen the Expression box is greyed out.  Why is this feature not available?

tbrink_DOIT · Answer

Thank you @EMani.  The only thing I can think of is the arcade output data type may be a string so ESRI limits its use.

EMani · Answer

Hi @tbrink_DOIT

I have tested, and you are correct, 3 seems to be the maximum. I can't see anything in the Apply a style documentation to explain this.

You could add a "leftover" field and calculate in the Data tab with an expression.

return $feature.population - ($feature.a + $feature.b + $feature.c + $feature.d + $feature.e)

Then add this leftover field in styles.

Note: This calculation is one-time only. If your data is dynamic or updated regularly, the expression would, for example, need to be a simple scheduled Notebook script, included in your edit form or calculated in Pro with attribute rules before overwriting, depending on your edit workflow.