topic Re: Null if Statement in Calculated Field in Data Management Questions

Null if Statement in Calculated Field

ThomasKelly — Thu, 13 Feb 2020 11:47:19 GMT

I have a column in an attribute table that has a mixture of nulls and data. I wish to create a new column that will return a "yes" if there is data in the column being checked and "no" if it is a null. I have tried a variety of python functions but I keep getting an error similar to the below:

ERROR 000539: File "<expression>", line 1
updateValue(1E+21.0)
^
SyntaxError: invalid syntax
Failed to execute (CalculateField).

I have tried the following :

X = updateValue(!field!)

def updateValue(value):
   if value == None:
   return 'no'
   else: return "yes"

Any help would be most appreciated.

Re: Null if Statement in Calculated Field

DanPatterson_Retired — Sun, 12 Dec 2021 00:38:38 GMT

/blogs/dan_patterson/2016/08/14/script-formatting

your indentation was wrong and the code block (eg lines 3-6 or 17-20 ) need to be placed in the code section and the expression (line 10 or 24) in the expression line.

Make the field (!some_field!) active, python parser, put in the code in the code block and the expression in its place and run.

Also don't use == None, use ... is None ...

you don't need your extra else since it will bypass to line 6 if value is not None

# for string field

def updateValue(value):
   if value is None:
       return 'no'
   return "yes"

# calling expression


updateValue(!some_field!)


# ------------------------
# for numeric field


def updateValue(value):
   if value is None:
       return -999
   return value

# calling expression

updateValue(!some_field!)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Null if Statement in Calculated Field

ThomasKelly — Thu, 13 Feb 2020 12:15:46 GMT

Hi Dan,

Thank you for the response, I have tried both of these and whilst both expressions are valid I am still returning the following for both:

ERROR 000539: File "<expression>", line 1
updateValue(1E+21.0)
^
SyntaxError: invalid syntax
Failed to execute (CalculateField).

The (!some_field!) is of data type double ...

I cannot understand why the same error is returning, it should be a straightforward process.

Many thanks

Thomas

Re: Null if Statement in Calculated Field

DanPatterson_Retired — Sun, 12 Dec 2021 00:38:40 GMT

1e2
100.0

1e2.0
  File "<ipython-input-2-3dea3e3816b2>", line 1
    1e2.0
        ^
SyntaxError: invalid syntax‍‍‍‍‍‍‍‍

spot the difference?

Re: Null if Statement in Calculated Field

ThomasKelly — Thu, 13 Feb 2020 12:33:54 GMT

is it a decimal formatting issue ?

Re: Null if Statement in Calculated Field

JoshuaBixby — Thu, 13 Feb 2020 15:24:09 GMT

This question seems to come up in one form or another about every 6 months on GeoNet. I think it is important to understand what Dan is pointing out. Additionally, you can use a Python conditional expression to achieve the result while not needing to define a code block:

"NO" if !field! is None else "YES"‍