Replace occasional Space with Underscore using Python parser of ArcGIS Field Calculator?

Question

I am creating a model which will give me two string values, one which reads exactly what is in a field and another which automatically replaces any Space with an "_". I have used Calculate Value tool, and entered in the following:

Expression:

ReplaceName(%Value%)

Code Block:

def ReplaceName(name):
 return name.replace(" ", "_")

The result is an error:

ERROR 000539: Error running expression: ReplaceName(NoSpace1) 
Traceback (most recent call last):
 File "<expression>", line 1, in <module>
NameError: name 'NoSpace1' is not defined

I suspect because not all my Values have spaces

Model and table

How can I make this work?

Answer 1

You don't necessarily have to define a function for this one. Try this:

str(!PlaceName!).replace(' ', '')

The "not defined" error is related to the lack of quotes around the NoSpace1. This could be from the % on either side of the Value. Your expression should be

ReplaceName(!Placename!)

• Midavalo: or str(!PlaceName!).replace(' ', '_') for underscores
• E. Ballent: Thanks for your answer! however it didn't work! I tried several variations including the example you gave. Executing (Calculate Value): CalculateValue str(!PlaceName!).replace(" ", "") # String ERROR 000539: SyntaxError: invalid syntax (<expression>, line 1) Executing (Calculate Value): CalculateValue str(!Value!).replace(" ", "") # String ERROR 000539: SyntaxError: invalid syntax (<expression>, line 1)
• crld: Try double clicking the field name to put it in the expression; sometimes a dataset will have a field name prefix that doesn't show up in the attribute table. Also try changing the double quotes to single quotes. Also for the parser make sure you're using the PYTHON_9.3 option. Is the field calculator returning any values at all?

Answer 2

You do not need the field calculator for replace at all.

You can just use the Find & Replace tool which is accessed from the attribute-table which has the search/replace function the same way as in Excel, for example.

It also works for all columns simultaneously or can be set to search for whole values etc.

enter image description here

• E. Ballent: Thanks for your answer, but I need this to work inside of model builder, also I am not trying to change the value in the table. Ultimately both the value with the space and the value without a space are going to be used as inputs in a later portion of the model.

Answer 3

This may not be the most elegant of fixes, but it did work:

enter image description here

I found that the %Value% had to have Quotes and I used a try/except sequence to get around the possible lack of a space in some of the values.