Deleting duplicate features with ArcPy based on multiple attributes

Question

I want to write Python code that removes duplicate features from a table based on their attribute value. Within the code, a loop will iterate through multiple attributes to check if the value is Null. If the attribute is not null, it is assigned to a "keep list." If the attribute is null, it is assigned to a "delete list."

How can I compare multiple values (Null and not Null) within the same attribute?

(row[0]a and row[0]b)

import arcpy                

fc = "F:/path/"               
drTable = "F:/path/"          
workspace = "F:/path/"        

def main():                                                       
    arcpy.MakeFeatureLayer_management(fc, "fc_lyr")               
    arcpy.JoinField_management("fc_lyr", "OBJECTID", drTable, "OBJECTID", "KEEP_COMMON") 

    deleteList = []          
    keepList = []

    with arcpy.da.SearchCursor("fc_lyr", ['OBJECTID']) as cursor:
        for row in cursor:
            arcpy.SelectByLocation_management("fc_lyr", "ARE IDENTICAL TO", "fc_lyr", 
            "NEW_SELECTION") 
            if arcpy.GetCount_management("fc_lyr") >= 2:             
                with arcpy.da.SearchCursor("fc_lyr", ['attr1','attr2','attr3',]) as cursor:    
                    for row in cursor:                              
                        if row[0] is None and row[0] is None:       
                                                        #???
                        elif row[0] is None and row[0] is not None:  
                            deleteList.append(row[0])                
                        elif row[0] is not None and row[0] is None:  
                            deleteList.append(row[0])                
                        elif row[0] is not None and row[0] is not None:  
                                                         #???

Answer 1

If you want to use a cursor, try this:

...    
where = "{0} IS NULL OR {1} IS NULL OR {3} IS NULL".format(arcpy.AddFieldDelimiters(datasource="fc_lyr", field='attr1'), 
                                            arcpy.AddFieldDelimiters("fc_lyr", 'attr2'),
                                            arcpy.AddFieldDelimiters("fc_lyr", 'attr3'))

with arcpy.da.UpdateCursor("fc_lyr", ['attr1','attr2','attr3'], where) as cursor:    
    for row in cursor:                              
        cursor.deleteRow()

But I would guess this is faster:

...
arcpy.SelectLayerByAttribute_management(in_layer_or_view="fclyr", where_clause=where)
arcpy.DeleteRows_management(in_rows="fc_lyr")