Arcade or Python? To populate attribute table with a dynamic url

[EmmaLewison1]

We have a hosted feature class and would like to create a dynamic URL by concatenating a base URL with a field value, and then store the resulting URL in the attribute table.

I have successfully created the dynamic URL for the pop-up, and I have also used Python to generate the URL in a test copy of the data stored locally. Ideally, we would like this field to be populated automatically when a new feature is created and saved using the instant app/field map.

I am unsure of the best approach. One option could be to use an ArcGIS Notebook with Python, but my understanding is that this would need to be scheduled rather than run automatically when a feature is saved, which would not meet our requirements for downstream processing. Alternatively, is it possible to achieve this using Arcade or another method that updates the field at the point of feature creation?

[JonathanMcD]

@EmmaLewison1 you've got another option, if the url creation is not hugely time sensitive, to create a Data Pipeline and schedule that.

Otherwise, you can do this is Field Maps with an arcade expression. 

We calculate risk, repair times, and schedules in Field Maps based on the user input at that moment.