What are the commands that replace the MID, LEFT, or RIGHT functions? For example, I need to extract the 2nd character from a 3 character string field named MOO, and populate the field COW with that value. Simple, I am sure, but ...?
Have you checked out the Code samples -- Strings in the Field Calculator examples for ArcGIS Pro?
I encourage you to learn a bit of Python, which is what parser ArcGIS Pro is using. In Python, strings are sequences that can be indexed, sliced, and much more. In your case, the second character in a three character string is !string_field! .
Retrieving data ...