topic Re: Simple scripting help in Mapping Questions

Simple scripting help

stuartcassin1 — Mon, 13 Oct 2014 01:23:56 GMT

to assist with symbology, I'm trying to populate a column with alternate 1 & 0 so I can filter and symbolise alternate records. I need a simple method to auto complete a table of approx 5000 records. Can anyone help?

Re: Simple scripting help

DanPatterson_Retired — Mon, 13 Oct 2014 02:22:41 GMT

python processor, use the FID field or any other sequential field

>>> from math import fmod

>>> for i in range(20):

... if fmod(i,2) == 0:

... print 0

... else:

... print 1

...

.......etc

>>>

python parser, enable the code block this is the function to use and in the expression box you could use ones_zeros(!FID!) (ps... haven't tried the code block but the above python syntax is the key

from math import fmod
def ones_zeros(your_field):
  if fmod(your_field,2) == 0:  print 0
  else:  print 1

Re: Simple scripting help

stuartcassin1 — Mon, 13 Oct 2014 02:36:00 GMT

Thanks for the suggestion Dan,

Unfortunately that didn't work. I mistakenly forgot to mention I'm using ArcGIS Basic 9.3.1 on an enterprise licence and I'm pretty sure the PythonWin Application hasn't been installed. Is there a way I can do this via the field calculator or the command line window?

I'm afraid my scripting / coding skills are pretty much zero.

Re: Simple scripting help

TimothyHales — Mon, 13 Oct 2014 03:53:09 GMT

You should be able to just use the Mod operator in the Field Calculator:

[ObjectID] Mod 2

Re: Simple scripting help

stuartcassin1 — Mon, 13 Oct 2014 04:16:39 GMT

Thanks Timothy,

Any chance you could supply the full script for the Field calculator (9.3.1)? I have no idea what the Mod operator is.

Sorry - scripting dummy here.

Re: Simple scripting help

yiqi — Mon, 13 Oct 2014 06:00:51 GMT

I think it is just "mod", i mean, you can input "i=5 mod 2" which will make i=1. So, "[ObjectID] Mod 2", as Hales mentioned above, is what you can use directly.

Re: Simple scripting help

stuartcassin1 — Mon, 13 Oct 2014 21:58:36 GMT

Just some additional info for this question:

I'm using ArcGIS 9.3.1 Basic

I only have access to the command line window or the field calculator. All other scripting options are unavailable

I have pretty much no skills in scripting so really am looking for the complete answer (cut & paste??)

The only sequential field in the attribute table is the FID column.

Hopefully someone can help me with an appropriate code. Thanks

Re: Simple scripting help

RobertScheitlin__GISP — Mon, 13 Oct 2014 22:27:04 GMT

Stuart,

Timothy's code is the complete copy and paste code that you need to put in the field calculator.

The only difference is that your field would be:

[FID] Mod 2

Just Copy and Paste the above line in the Field Calculator window in ArcMap.

Re: Simple scripting help

stuartcassin1 — Mon, 13 Oct 2014 22:38:21 GMT

Thanks guys.

Worked perfectly.