Domain with Null option in Subtypes

[KatherineAlexander_WGS]

Hello, 

I am trying to use subtypes to auto populate fields in a feature class in Arcpro. In my subtypes I have domains set for some of the fields with default options. When I create a new feature I choose a subtype and the fields auto populate, but if I want to change the line from one sub-type to another where I want some of the fields with domains to be Null (which is how they are set up in the subtype). the field will not auto populate to null once one of the fields has been populate with options from other subtypes. 

I am trying to get the field to auto populate the filed to null so that i am forced to choose between my domain options for certain line types. 

Or if there is another way to get fields to auto populate as I create lines in my feature class other than subtypes suggestions would be greatly appreciated. 

Thanks

[Anonymous User]

you can use calculate field for this. 

in the calculate field window for the field you want set to null, set language to python and enter a code block something like this:

def reclass(variable):
if variable== "subtype":
     return ""

where "subtype" is the specific subtype you want to cause the field to become null. If the field is numeric then don't put it in quotes.

In the input box where is says "[name of field] =", put in reclass([subtype field]), where [subtype field] is the field that contains the subtype that determines whether or not you want the other field set to null. 

Does that make sense? I'm not sure I completely understand what you are trying to do, so it's possible that this won't help.