I am in the infancy stage with python and have no idea where to start. I simply want to replace values in a field from a feature layer with the values in a field from a table I joined (to the feature layer) using the Calculate Field tool in ArcGIS Pro.
Pretty straightforward in the Calculate Field geoprocess window - if you wanted to populate a field named "Box Name" with the values from the joined field "Second Layer.Box Name" you could either (in the calculate field text box at the bottom of the window that starts with the "=" symbol) type:
[Second Layer.Box Name]
with the VBScript radio button selected, or:
!Second Layer.Box Name!
with the Python radio button selected. Then just click "OK". Make sure that the new field you are calculating has the same Type (such as Text, Double, Short) as the one you are copying over. Or, as a Python command:
arcpy.CalculateField_management("Joined Layername", "Box Name", "!Second Layer.Box Name!", "PYTHON")