I succesfully wrote a script to render a Uniquevaluerenderer in a layer in ArcMAP using symbols from 4 parameters (values) read from the attribute table of the layer. I used ArcObjects and VBA, but with VBA support being discontinued in ArcGIS 10 I now want to convert this script using Python. Can anyone suggest some pointers or sample code.
Since ArcGIS 10.1, you can use UniqueValueSymbology to edit it.
Please follow ArcGIS Help 10.1 UniqueValuesSymbology section
However, Arcpy doesn't implement all of ArcObjects functions such as change to UniqueValueRenderer from the other renderers, and change each values symbol. So, If you have source code written in VBA and its works, then better way is migration it to ArcMap Addin. For more information, please follow bellow topic. http://help.arcgis.com/en/sdk/10.0/arcobjects_net/conceptualhelp/index.html#/Building_add_ins_for_ArcGIS_Desktop/0001000000w2000000/