How to read XY, get raster value and then update field?

Question

I've written a script to run through a point layer, using the SearchCursor in the data access module and then read the XY values. Within the with statement, I then use GetCellValue to get the elevation values and print them.

What I'd like to do is go one step further and write the value to a field in the row. Is there a way to do this? I can use CalculateField, but that'll be slow as it'll have to use a query to limit itself to the current row. I can also possibly use a list to write the values to and then run through the list and update the fields using the UpdateCursor, but I think that'll be slow too.

Is there a way to do this inside the with statement?

import arcpy

##arcpy.AddField_management('C:\Data\Surveyed.shp', 'Z', 'DOUBLE')

with arcpy.da.SearchCursor('C:\Data\Surveyed.shp', ['SHAPE@XY']) as cursor:
    for row in cursor:
        result = arcpy.GetCellValue_management('Database Connections\DC_SDEEBG_gisp.sde\SDEEBG.GIS.SRTM_DEM_NSWVICTAS_1SEC', str((row[0])[0]) + " " + str((row[0])[1]), "1")
        CellValue = float(result.getOutput(0))
        print CellValue

Answer 1

Yes - you should use arcpy.da.UpdateCursor instead of arcpy.da.SearchCursor.

Elaboration:

This is what I would try:

import arcpy

arcpy.AddField_management('C:\Data\Surveyed.shp', 'Z', 'DOUBLE')

with arcpy.da.UpdateCursor(r'C:\Data\Surveyed.shp', ('SHAPE@XY', 'Z')) as cursor:
    for row in cursor:
        result = arcpy.GetCellValue_management('Database Connections\DC_SDEEBG_gisp.sde\SDEEBG.GIS.SRTM_DEM_NSWVICTAS_1SEC', str((row[0])[0]) + " " + str((row[0])[1]), "1")
        CellValue = float(result.getOutput(0))
        print CellValue
        #  Use CellValue to set the second value (Z)
        row[1] = CellValue
        #Update the FC row
        cursor.updateRow(row)