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arcpy.CalculateField_management(featureclass, "field3", "!field1! * !field2!", "PYTHON_9.3","#")
arcpy.CalculateField_management(featureclass, "field3", "!field1! * !field2!", "PYTHON_9.3","#")
expr = "!{0}! * !{1}!".format("FIELD1", "FIELD2") arcpy.CalculateField_management(featureclass, "FIELD3", expr, "PYTHON_9.3")