topic Re: Field Calculator in Data Management Questions

Field Calculator

LianaSmith — Wed, 18 May 2016 13:09:56 GMT

I need to exclude all values that contain any letter from one of the fields. Basically only integers should be left. What code (Python/VB) do I have to put in field calculator for that?

Thanks!!!

Re: Field Calculator

DanPatterson_Retired — Wed, 18 May 2016 13:14:06 GMT

I covered that here Query to have only numeric values in the field

Add a numeric field (integer)

Use the python parser and use the syntax given

int("".join([i for i in !YourFieldName! if i.isdigit()]) )

Re: Field Calculator

LianaSmith — Wed, 18 May 2016 13:31:22 GMT

Dan, it does not work. That's what I get:

Re: Field Calculator

DanPatterson_Retired — Wed, 18 May 2016 14:31:59 GMT

Ohhhh... You failed to mention that some of the entries don't have numbers in them.

So... you have to create a text/string field instead and delete the int( ) part. Now of course, if there is no numbers in the entry, you will get back an empty string.

The question remains

do you want the output to only be numbers?
what do you want to do if there are no numbers in the entry?
are you good with a text representation of a number? or does it have to be a number?

The rule set will determine the format of the new field, the values it returns and the outputs it will return... especially if you want this as an automagic all encompassing solution.

Re: Field Calculator

LianaSmith — Wed, 18 May 2016 14:38:23 GMT

Sorry for not mentioning them...I think I can not use field calculator at all.. I dont want to change the values that have letters, I need them to be deleted...

Re: Field Calculator

TedKowal — Wed, 18 May 2016 15:55:06 GMT

If you want to simply blank out any entry in which GROUTE contains a letter then perhaps you could do this (test on a copy first!):

Since GROUTE could contain letters then it cannot be a number....

GROUTE = "" if any(b.isalpha() for b in !GROUTE!) else !GROUTE!

Re: Field Calculator

LianaSmith — Wed, 18 May 2016 18:53:01 GMT

Thank you so much Ted! It worked. I assigned empty value for all non-numeric values and then excluded them by querying FC to FC

Re: Field Calculator

LianaSmith — Wed, 18 May 2016 19:47:36 GMT

Ted, I exported the field calculator function to Python script and I get error now..

Do you have any idea why? Thanks again

> Error ocurred in:
File "P:\Batch\J420992\CODE\PYTHON\J420992_C1_Customers.py", line 66, in <module>
arcpy.CalculateField_management(WCSCUSTOMERCOPY, "GROUTE", " \"\" if any(b.isalpha() for b in !GROUTE!) else !GROUTE!", "PYTHON_9.3", "")

> Error Class is:
<class 'arcgisscripting.ExecuteError'>

> Available error details are:
ERROR 000539: IndentationError: unexpected indent (<expression>, line 1)
Failed to execute (CalculateField).

Re: Field Calculator

DanPatterson_Retired — Wed, 18 May 2016 22:00:22 GMT

I new all this sounded familiar!!!

How to remove spaces with Calculate field in ArcMap?

Re: Field Calculator

curtvprice — Sat, 11 Dec 2021 15:23:46 GMT

You have an extra space:

" \"\" if any(b.isalpha() for b in !GROUTE!) else !GROUTE!"
 ^

I use single quotes to wrap double quotes; easier to read:

'"" if any(b.isalpha() for b in !GROUTE!) else !GROUTE!'

Re: Field Calculator

LianaSmith — Thu, 19 May 2016 13:14:21 GMT

I removed space and got this error...

Then I tried to use single quotes like you wrote and got this:

Re: Field Calculator

DanPatterson_Retired — Thu, 19 May 2016 14:10:56 GMT

The following works as a field calculator expression in Pro and also in ArcMap. Check the details

Re: Field Calculator

LianaSmith — Thu, 19 May 2016 14:12:48 GMT

Thank you !

Re: Field Calculator

TedKowal — Thu, 19 May 2016 16:07:46 GMT

LOL I just got back to the office.... I only jumped in because it sounded like she only wanted to ignore those rows that had a character in it... When using python, now, I avoid nulls and put an empty/blank/unused code filter and delete in a two step process since I do not trust finding nulls yet in python.

Liana I am happy you got it worked out! That's all the matters!

Re: Field Calculator

LarryStout — Sat, 11 Dec 2021 15:23:48 GMT

Liana,

Using Python, the Codeblock (Pre-logic Script Code) would be:

def result(value):
    import re
    return ""  if re.search("[a-zA-Z]", value) else value

And the calculation would be:

result( !<FIELD_NAME>! )

Be careful overwriting the same field. You can't undo it unless you start an edit session first.

Larry