Please correct me if I'm wrong, but it sounds like you want a script you can execute at-will, or do you want this to run automatically as new features are added/populated?
The expressions used should be simple enough... without seeing the fields and values, I would imagine it would look something like what's below.
var x = $feature.FID;
var y = $feature.[Field Name] //replace [Field Name] with the actual field name. This field may need to be passed/added as an array since I'm guessing you'll want to sum all the values and not individual record values
var z = $feature.[Field Name] //replace [Field Name] with the actual field name
if (x == ?) { // replace ? with the value you want to detect. if is a conditional statement that evaluates one thing to another and runs commands if the condition(s) are met.
sum ([y]); // The sum function can accept an array inside ([]) these brackets, or a number string input as (1,2,3)
z=y;
return z;
} else {
NULL
}
all the expressions I've written in arcade have generally been simple, so you may need to enlist help from those more experienced to get the sum function to work the way you envision; however, if you paste the above expression into an arcade editor, you should be able to modify and run it as I describe in the parts marked by //.
Hope this helps!
