ArcGIS Pro Arcade Expression for various characters in the Asset Id field

Question

I'm looking for an arcade expression for arcgis pro symbology. Involves the Asset ID field to symbolise based on text within an asset ID.

Say if the asset ID contains C2 then blue (for instance), or if the asset ID contains C1, C3 or GAS, so on and so forth. Imagine a treatment plant with lots of pipes of different colors all based off different common text within the asset ID.

How would the arcade expression look if trying to achieve this?

Maybe another way of putting it would be: What would the symbology expression be if i wanted; 5 different colors based off different text in the asset ID field: "C1", "C2", "C3", "GAS" and "AIR"

Im thinking the answer to my question might involve the "Contains ()" function. How does a expression look when using the contains function.

I am using the code below as a symbology expression with limited success.

var disp_txt = $feature.ASSET_ID

if (Find("-C2-", disp_txt, 0)>-1) {
    return "C2";
} else if (Find("-C3-", disp_txt, 0)>-1) {
    return "C3";
} else if (Find("-C1-", disp_txt, 0)>-1) {
    return "C1";
} else if (Find("GAS", disp_txt, 0)>-1) {
    return "BIOGAS";
} else if (Find("RS", disp_txt, 0)>-1) {
    return "RAW SLUDGE";
} else if (Find("DSL", disp_txt, 0)>-1) {
    return "DSL";
} else if (Find("AIR", disp_txt, 0)>-1) {
    return "AIR";
} else if (Find("-G-", disp_txt, 0)>-1) {
    return "GRIT";
} else if (Find("PD", disp_txt, 0)>-1) {
    return "PLANTDRAIN";
} else if (Find("TD", disp_txt, 0)>-1) {
    return "TANKDRAIN";
}

Answer 1

Although a workable solution was found, large else if blocks can usually be replaced with cleaner functions, regardless of the language. For ArcGIS Arcade, two functions that can often replace large else if blocks are Decode and When.

Looking at the sample data in the question comments, the asset IDs appear regular enough in structure that using Split and Decode can be used to replace else if:

var txt = $feature.ASSET_ID;
Decode(
  Split(txt, '-')[1],
  'C2', 'C2',
  'C3', 'C3',
  'C1', 'C1',
  'GAS', 'BIOGAS',
  'RS', 'RAW SLUDGE',
  null
);

Answer 2

I think you are getting confused with what the expression does. Below is some data, simply set to unique values on a field called regions:

I click on the expression button and create the following expression, similar to what you are doing with your asset ID field

Notice the classes change to the output text created by the expression:

Here in lies the possible confusion you have, the expression changes only the class names, it has nothing to do with the symbology. YOU change the symbology by simply double clicking on the coloured dots (the brown/green in my example below) and change them to what ever you want.

The expression builder has no capability in altering the symbology that is applied to the class that the expression is outputting. You set that manually. You can alter symbology programmatically through something like the CIM module, but that requires advance understanding of the object model and programming in python.

Answer 3

Here is your solution in practice:

var txt = $feature.ASSET_ID
if (Find("-C2-", txt, 0)>-1) {return "C2";}
else if (Find("-C3-", txt, 0)>-1) {return "C3";}
else if (Find("-C1-", txt, 0)>-1) {return "C1";}
else if (Find("GAS", txt, 0)>-1) {return "BIOGAS";}
else if (Find("RS", txt, 0)>-1) {return "RAW SLUDGE";}

Looks pretty similar to the original code submitted at the start, so i was on the right track. I think some confusion, lay in the assumption i had attribute data that i could modify. This was protected data (could not add fields) and only had asset ID which is a unique reference number.