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Arcade & Calculate field with text and incrementing number with a starting number and an interval

AGP

I have Python calculate field expression (.cal file) that does this but I'm trying to migrate it to Arcade.

It's not working. The number part is not incrementing and I guess it has to do with me not being able of defining 'rec' as a global variable.

This is the Python expression. How do I migrate the 'global rec' line to Arcade?

#Params
val_counter = 2498
prefix = 'PP_'
interval = 1
# -------------------------------------------
# Function
rec=0
def SetIDcode(val_counter, prefix, interval):
  global rec
  if (rec == 0):
    rec = val_counter
  else:
    rec += interval
  return (prefix+ str(rec))

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jcarlson

Here's the equivalent of your function in Arcade:

var rec = 0
function SetIDcode(val_counter, prefix, interval){
    if (rec == 0){
        rec = val_counter
    } else {
        rec += interval
    }
    return prefix + rec
}

Here's me testing it with the sample parameters you gave:

Can you explain a bit more about how you use this, though? Is the rec variable always going to be 0, or are there other parts of the expression that alter it?

AGP

The rec variable is 0 for the first feature, so the returned valued is prefix + val_counter (PP_2498).

But then the rec varaible should get the value in val_counter for the second feature returning prefix + val_counter + interval (PP_2499) and incrementing by interval for each next feature (PP_2500, 2501,...).

Your function (mine was like yours) returns PP_2498 for every feature.

JoeBorgione

What if you use an attribute rule that grabs a the next value from a geodatabase sequence?

jcarlson

I see. That will only work for an iterative loop, not in the Field Calculate profile. When writing a field calculation in Arcade, you have to imagine that you're already in the loop, as the expression will be evaluated for every feature.

In Arcade, we can access and work with the other values in the layer, so you've got some options. Is the code stored only as a string, or is there some way to access the numeric val_counter without the prefix?

Also, what values are in this field right now? Are they null? Does the val_counter correspond to the number of records in the layer?

AGP

The user inputs the val_counter value according to their needs, as well as the prefix and interval values.

I guess interval will always be 1 but they are given the option to decide.

AGP

I thought of the possibility of using Batch calculation rules so users would execute the rules whenever they need it. We should just publish our feature services with the validation capability enabled and create a database sequence (if the db admin approves).

The problem here is that the user decides the layer and field they will populate so attribute rules are not an option. Using a calculate field expression is more convenient here but we wanted to use Arcade instead of Python.

Brian_Wilson

Using Arcade when you don't have to seems like jumping through extra hoops to me. I have not seen any upside to it yet.

I am betting Arcade will go away before I need to learn it.

Brian

jcarlson

If you're working on desktop, you probably don't have to learn it, but a lot of the web stuff is being built around it. I use Arcade in Pro when I know the layer / expressions / etc. will need to transfer 1:1 to a web map or field app.

JoeBorgione

I'd be really surprised if Arcade has a short shelf life. I'm sold on attribute rules and without Arcade, they don't happen.

ArcMap and ArcCatalog have one foot in the grave, there's just no denying it.

By the end of this week, all this stuff will be in my rear-view mirror, but I've had a ton of fun with Unix Scripts, AML, PERL, VB, VBA, Python, and Arcade over the years in various flavors of ESRI-Arc* products. You may notice I left out Avenue. IMHO that along with ArcView was a mistake and luckily did have a short shelf life. (And somehow I never spent much time or energy with it...)

DanPatterson

"Avenue"... now "Arcade" .

I got burned once learning a proprietary language (google esri history) that you can't use elsewhere.

I will stick to Python (and other languages), . Besides, python is even beating out the other curly bracket languages in terms of wide spread use. If you have to do the cloudy map stuff, you may be stuck but don't use it as a replacement for learning other languages that you can use outside of the "Arc"

Brian_Wilson

In Python this is the shortest code I could come up with that does what you seem to want.

rec=2497
def fn():
  rec += 1
  return 'pp_'+str(rec)

You can dress it up with comments and constants and pass in variables as args but this is all you need.

I could be all wrong on this but after experimenting I conclude that in Arcade you just get a simple expression and each time the field calculator is invoked on a row in your table it will set all variables back to their initial state. In the field calculator there is no global memory.

For what you are trying to do therefore, use the Python.

Therefore there is no equivalent that I can give you, you will just get the same value on each row.

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