I have tried examples from the GIS support website and many more, but I cannot figure out how to get a codeblock for a field calculation to work within ArcPy.

Part of my code is underneath, it is a continuation of a table being added (multiple calculate fields). However the earlier calculations do not use a codeblock, the last one does. As a side note to the codeblock section, wing.IDE will not let me indent the code further than this. I hope that that is not where it goes wrong


Codeblock_for_geometry_10 = """
    def val:
    if [AFSPRAAK] = 'Huur' then
    val = 'D102'
    elseif [AFPSRAAK] <> 'Huur' then
    val = 'D101'
    end if

Field calculation (RVB_geometry_9 being the previous calculation on the table):

RVB_geometry_10 = arcpy.CalculateField_management(RVB_geometry_9, "NIVEAU_3", "val", "VB", Codeblock_for_geometry_10)

The error I get: A field name was not found or there were unbalanced quotation marks.

As far as I can tell the quatation marks are correct and the fieldnames are aswel. I would like to learn what I am doing wrong here for future calculations.

  • I am not sure if this is the problem or not, but I think you should close the block with another """ three double quotes.
    – ahmadhanb
    Commented Apr 10, 2020 at 7:22
  • 1
    Ah, my apologies! I missed that out in the copy paste to the post. It is closed with another three """, I will adjust it now.
    – Remko
    Commented Apr 10, 2020 at 7:23

1 Answer 1


You seem to be mixing python and VB syntax (def is python). Stick to python.

Here's a python version:

code_block = """
def my_function(my_field):
    if my_field == 'Huur':
        return 'D102'
        return 'D101'

result = arcpy.CalculateField_management(RVB_geometry_9, "NIVEAU_3", "my_function( !AFPSRAAK!)", "PYTHON", code_block)

A quick way to generate this is to run the Calculate Field tool from ArcMap, open the geoprocessing->results window, right click the result and select "Copy as python snippet".

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