topic Re: Code in field calculator does not 'refresh' in Python Questions

Code in field calculator does not 'refresh'

AndersKMG — Fri, 16 Sep 2022 09:25:43 GMT

Hello. I have a python code in the ArcMap field calculator that translates numbers in the Id-column to text in another column in the same attribute table. In the pre-logic-script It looks like this:

def reclass(Id): if (Id == 0): return "AAA" if (Id == 1): return "BBB" if (Id == 2): return "CCC" if (Id == 3): return "DDD" if (Id == 4): return "EEE" if (Id == 5): return "FFF" if (Id == 6): return "GGG" else: return "<Null>"

and in the other box:

reclass(!Id!)

The problem is that this code disapears every time I shut down arcMap, and have to be re-loaded when I add anything. For example if I add an object with id-class 2 it doesn't automatically writes CCC in the new column iuntill I have re-runed the script.

Is there some way I can automatically run this script as soon as I open / change anything the attribute table?

Re: Code in field calculator does not 'refresh'

JohannesLindner — Fri, 16 Sep 2022 11:25:27 GMT

For ArcMap, there's the Attribute Assistant.

For ArcGIS Pro, there are Attribute Rules.

Re: Code in field calculator does not 'refresh'

BlakeTerhune — Fri, 16 Sep 2022 14:16:53 GMT

Attribute Rules in ArcGIS Pro is the best solution here. I will add that you can write a Python script that to perform the calculate field operation on your data and schedule it to run as a task. So every night, or even every hour, the script could run to calculate the values.

Re: Code in field calculator does not 'refresh'

Anonymous User — Thu, 22 Sep 2022 13:07:53 GMT

Two tips for you: using "<Null>" will enter it as a string and not a true Null.

You can avoid chaining if statements by using a switch case (dictionary lookup) construct.

def reclass(Id): classDict = { 0: "AAA", 1: "BBB", 2: "CCC", 3: "DDD", 4: "EEE", 5: "FFF", 6: "GGG"} return classDict.get(Id) # <- returns the value if found in the dictionary or the default true Null #return classDict.get(Id, '<Null>') # <- returns the value if found in the dictionary or the string <Null> as the default