topic Re: python script for renaming attributes in Python Questions

python script for renaming attributes

TilottamaGhosh — Fri, 29 Jun 2012 09:33:01 GMT

Hi,

I am trying python scripting for the first time and couldn't achieve what I am trying to do.

So, I have five types of Landcover - Drain, Lake, River, Water Body, and Canal. I want to name all of these 'Water'.

I figured that I could do it with this small script- !LANDCOVER!.replace("River","Water") in Field Calculator.

But, I would want to do all of them together using a python script in the 'Field Calculator'. I tried with some if, else statements, but they didn't work.

Can someone please help me with this?

I will look forward to your response.

Thanks in advance,

Tilottama

Re: python script for renaming attributes

MarcinGasior — Fri, 29 Jun 2012 10:10:34 GMT

In Field Calculator select Python parser and check Show Codeblock.

Pre-Logic Script Code:

def reclass(landcover):   if landcover in ("Drain", "Lake", "River", "Water Body", "Canal"):     return "Water"   else:     return landcover

LANDCOVER =
reclass(!LANDCOVER!)

Re: python script for renaming attributes

TilottamaGhosh — Mon, 02 Jul 2012 04:39:49 GMT

Hi M,

Thanks for your reply. I tried with the code block you had sent. However, I was not able to make it work. I tried running the code selecting the 'type' as string. I am attaching a word document which shows the code as I ran it and the error in the Geoproessing result window. Could you please point out my mistake? Thanks again for your help. I will look forward to your reply.

Best Regards,

Tilo

Re: python script for renaming attributes

MarcinGasior — Mon, 02 Jul 2012 07:06:33 GMT

Python is case sensitive - Reclass in not the same as reclass
Function is defined as reclass and reclass(!LANDCOVER!) should be used.

Moreover, try to use exactly the same code in Pre-Logic area as I provided.
This code replaces every occurence of "Drain", "Lake", "River", "Water Body", "Canal" to "Water"
and other values are leaved untouched.

Beware that when you make calculations on existing field LANDCOVER, its original values cannot be reverted. (Backup copy of the data may be handy).

Re: python script for renaming attributes

TilottamaGhosh — Mon, 02 Jul 2012 07:28:03 GMT

Hi Marc,

Thanks a bunch! It worked! I copied and pasted the code 'as it is' and it worked.

Thanks very much.

Best Regards,

Tilottama