topic Re: Using Conditional Statements to add from different fields in Field Calculator (Python) in ArcGIS Pro Questions

Using Conditional Statements to add from different fields in Field Calculator (Python)

JoshBillings — Wed, 24 Feb 2021 17:04:29 GMT

Hey all,

I am new to Python. I am currently trying to write a calculation using Python in the field calculator ONLY IF another field equals a specific value.

For instance, I have a MAINTENANCECOMPLETE field, a MAINTENANCETYPE field, a DEFMAINTENANCE field, and a COST field.

I want the MAINTENANCECOMPLETE field to populate the sum of DEFMAINTENANCE and COST only if MAINTENANCETYPE is equal to "DM General."

Here is what I currently have:

Code Block:

def ifBlock(maintenanceType):
if maintenanceType== 'DM General'
return !DEFMAINTENANCE! - !Cost!

Actual Code:

ifBlock(!MaintenanceType!)

How should I write this differently?

Let me know if I can clarify in any way.

Re: Using Conditional Statements to add from different fields in Field Calculator (Python)

JoshuaBixby — Wed, 24 Feb 2021 18:26:26 GMT

You don't have to use the code block for this, you can use Python conditional expression, a.k.a, ternary operator: 6. Expressions — Python 3.9.2 documentation

Expression:

!DEFMAINTENANCE! + !COST! if !MAINTENANCETYPE! == 'DM General' else !MAINTENANCECOMPLETE!

Re: Using Conditional Statements to add from different fields in Field Calculator (Python)

JoshBillings — Tue, 02 Mar 2021 20:24:22 GMT

Genius. Thank you. I was making it more difficult than I should have.

What if I had several attributes for MAINTENANCETYPE?

When I try to use this below, it populates all fields with the difference of DEFMAINTENANCE - COST even if it doesn't meet the criteria:

!DEFMAINTENANCE! - !COST! if !MAINTENANCETYPE! == 'DM General' or 'DM Asset Protection' or 'DM Priority Safety Concern' else !MAINTENANCECOMPLETE!

Any way to do this @JoshuaBixby ?

Re: Using Conditional Statements to add from different fields in Field Calculator (Python)

JoshuaBixby — Wed, 03 Mar 2021 15:29:44 GMT

This should work:

!DEFMAINTENANCE! - !COST! if !MAINTENANCETYPE! in ('DM General','DM Asset Protection','DM Priority Safety Concern') else !MAINTENANCECOMPLETE!