topic Re: Python calculation in field calculator in Geoprocessing Questions

Python calculation in field calculator

KathrinSchulte-Braucks — Mon, 17 Oct 2011 08:43:47 GMT

Hello,

I'm trying to do some simple calculation within the field calculator using Python instead of VB and keep on getting error messages.

Pre-logic script code:

def rad (value):
  return math.sqrt(value / math.pi( ) )

Expression:
AEQU_RAD= rad (!area!)

I get the error message, that "float object is not callable". Field type is double.

Re: Python calculation in field calculator

DanPatterson_Retired — Sat, 11 Dec 2021 20:12:55 GMT

pi() is the problem, see below

>>> import math
>>> print math.pi
3.14159265359
>>> print math.pi()
Traceback (most recent call last):
  File "<interactive input>", line 1, in <module>
TypeError: 'float' object is not callable

Re: Python calculation in field calculator

KathrinSchulte-Braucks — Mon, 17 Oct 2011 13:06:37 GMT

Thank you so much, now it works. I just clicked on the proposed function in the box on the right. The implemented syntax in the box was math.pi(), so I assumed this is the correct syntax.

Re: Python calculation in field calculator

ChrisFox3 — Tue, 18 Oct 2011 17:27:14 GMT

Hi Kathrin,

Thank you for pointing out this issue. I logged a bug for math.pi and math.e constants being listed as functions in the field calculator, NIM074191.

Re: Python calculation in field calculator

KathrinSchulte-Braucks — Thu, 20 Oct 2011 08:14:40 GMT

Thanks for processing this issue!