topic Field Calculator Python - Comparing one field to the next in Python Questions

Field Calculator Python - Comparing one field to the next

MikeMacRae — Mon, 02 Apr 2012 17:06:24 GMT

I have the following syntax in a coded block script in field calculator using python and a personal geodatabase feature class:

if !ECOSITE! == !ECOSITE_1!:     test = "Same" else:     test = "Inclusion"  COMPARE_FIELDS =  test

Maybe it's a Monday morning and I just can't seem to figure out why it's erroring out, but it is. I am getting one or 2 error numbers....the generic 999999 and another generic one 000989. Neither one of which are revealing why the calculator doesn't like my equation. Can anyone identify what it going wrong? I've also attached a screenshot of my field calculator.

Thanks,
Mike

[ATTACH=CONFIG]13186[/ATTACH]

Re: Field Calculator Python - Comparing one field to the next

CoryMacNeil1 — Sat, 11 Dec 2021 11:55:28 GMT

Hi Mike,

Python is a bit different for its setup. You need to have a function definition and a call to the function. Try this:

def TestFields (Field1,Field2):
    if Field1 == Field2
        test = "Same"
    else:
        test = "Inclusion"

COMPARE_FIELDS = 
TestFields(!ECOSITE!,!ECOSITE_1!)

I hope this helps.
Cheers,
Cory

Re: Field Calculator Python - Comparing one field to the next

MikeMacRae — Sat, 11 Dec 2021 11:55:31 GMT

thanks for the response Cory. Unfortunately this still is returning the same errors.

I tried:

def TestFields ( !ECOSITE! , !ECOSITE_1! ):
    if !ECOSITE_1! == !ECOSITE!:
        test = "Same"
    else:
        test = "Inclusion"

COMPARE_FIELDS = 
TestFields(!ECOSITE!,!ECOSITE_1!)

I even tried returning the "test" variable and same deal...I'm stumped.

Also, I don't think you need to define a function in the field calculator in code block mode. I have other conditional scripts that work without defining them as functions.

Thanks,
Mike

Re: Field Calculator Python - Comparing one field to the next

DarrenWiens2 — Mon, 02 Apr 2012 17:50:40 GMT

Mike, you're getting close. It's a funny syntax thing - in the expression you reference fields (e.g. !ECOSITE!), then they turn into arguments/variables in the function (e.g. ECOSITE). Then, "return" the values.

def TestFields ( ECOSITE , ECOSITE_1 ): # these reference individual values     if ECOSITE_1 == ECOSITE:         return "Same"     else:         return "Inclusion"  COMPARE_FIELDS =  TestFields(!ECOSITE!,!ECOSITE_1!) # these reference the field to grab individual values

Re: Field Calculator Python - Comparing one field to the next

CoryMacNeil1 — Sat, 11 Dec 2021 11:55:34 GMT

Hi Mike,

With Python, I am quite certain you do have to define a function.

Try this (I forgot the return in my first posting):

def TestFields (Field1,Field2):
    if Field1 == Field2:
       return "Same"
    else:
        return "Inclusion"

TEST =
TestFields( !ECOSITE!, !ECOSITE_1! )

I just did a sample and it works. If it does not work for you, let me know what data types your two ECOSITE fields are.

I hope this helps.
Cory

Re: Field Calculator Python - Comparing one field to the next

MikeMacRae — Mon, 02 Apr 2012 18:21:06 GMT

Hey thanks folks!

Darren that works. I started playing around with returning the values. Thanks for pointing me in the right direction

Cory, looks like you followed up the same thought. Also, you are right about defining functions. I was looking at an older script of mine, but it turns out it was in VB. My bad!

Mike