https://community.esri.com/t5/python-questions/convert-excel-formula-to-python-2022/m-p/1136335#M63570 <P>You need to use a cursor.&nbsp; Something like this, but keep in mind that it only works if your object_id's are grouped like in your image. they are not, you can use an order by sql clause in the cursor to group them in the desired order.</P><LI-CODE lang="python">previous_object_id = None previous_vertex_val = 1 with arcpy.da.UpdateCursor(fc, ["object_id", "Vertex"]) as cursor: for row in cursor: # check if the current object_id is the same as the previous. if str(row[0]) == str(previous_object_id): # set vertex to current vertex value row[1] = previous_vertex_val # increase the vertex previous value by 1 previous_vertex_val += 1 else: # new object_id, reset the object_id and previous_vertex val # reset the object_id and vertex value to 1 previous_object_id = str(row[0]) previous_vertex_val = 1 # set vertex in the fc to 1 row[1] = previous_vertex_val # update the row cursor.updateRow(row)</LI-CODE><P>&nbsp;</P> Mon, 24 Jan 2022 13:00:32 GMT Anonymous User 2022-01-24T13:00:32Z https://community.esri.com/t5/python-questions/convert-excel-formula-to-python-2022/m-p/1136310#M63569 <P>Hello everybody, i would like to be helped form you for a excel formula , that i need some help to convert to python code for GIS attributes.<BR /><BR />I have this excel formula """=IF(A2&lt;&gt;A1,1,B1+1)"""" that give valued number from 1,2,3,4, etc to Vertec column when the other row value change.<BR /><BR />For example when the object_ID change form 5/75 to another value the numer starts counting form the 1,2,3,4,5 etc until another Object_id changes again.<BR /><BR />Photo attach.</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="Sami04_1-1643017687586.png" style="width: 400px;"><img src="https://community.esri.com/t5/image/serverpage/image-id/32082iAD1BA159017AF396/image-size/medium?v=v2&amp;px=400" role="button" title="Sami04_1-1643017687586.png" alt="Sami04_1-1643017687586.png" /></span></P><P>&nbsp;</P><P>&nbsp;</P><P>&nbsp;</P><P><BR /><BR /></P> Mon, 24 Jan 2022 10:08:47 GMT https://community.esri.com/t5/python-questions/convert-excel-formula-to-python-2022/m-p/1136310#M63569 Sami04 2022-01-24T10:08:47Z https://community.esri.com/t5/python-questions/convert-excel-formula-to-python-2022/m-p/1136335#M63570 <P>You need to use a cursor.&nbsp; Something like this, but keep in mind that it only works if your object_id's are grouped like in your image. they are not, you can use an order by sql clause in the cursor to group them in the desired order.</P><LI-CODE lang="python">previous_object_id = None previous_vertex_val = 1 with arcpy.da.UpdateCursor(fc, ["object_id", "Vertex"]) as cursor: for row in cursor: # check if the current object_id is the same as the previous. if str(row[0]) == str(previous_object_id): # set vertex to current vertex value row[1] = previous_vertex_val # increase the vertex previous value by 1 previous_vertex_val += 1 else: # new object_id, reset the object_id and previous_vertex val # reset the object_id and vertex value to 1 previous_object_id = str(row[0]) previous_vertex_val = 1 # set vertex in the fc to 1 row[1] = previous_vertex_val # update the row cursor.updateRow(row)</LI-CODE><P>&nbsp;</P> Mon, 24 Jan 2022 13:00:32 GMT https://community.esri.com/t5/python-questions/convert-excel-formula-to-python-2022/m-p/1136335#M63570 Anonymous User 2022-01-24T13:00:32Z