topic Re: Bugs in script to populate an empty attribute field in Transportation Questions

Bugs in script to populate an empty attribute field

Anonymous User — Fri, 16 Aug 2013 21:36:36 GMT

Original User: sellingfloe

Here is a copy of my script.

[ATTACH=CONFIG]26766[/ATTACH]

I am attempting to populate a blank field (Veg_Height) in my shapefile attribute table with text of my own choosing depending on the value in field Class_name.

e.g. if Class_name = "Grass", change the blank Veg_Height field to "Short", if Class_name = "Trees", change the blank Veg_Height field to "Tall" etc.

Unfortunately, at the moment, I keep getting errors when I try to run this in model builder. Can anyone suggest any changes I could make?

Thanks 🙂

Re: Bugs in script to populate an empty attribute field

AmyKlug — Sat, 11 Dec 2021 09:48:14 GMT

Here is a copy of my script.

[ATTACH=CONFIG]26766[/ATTACH]

I am attempting to populate a blank field (Veg_Height) in my shapefile attribute table with text of my own choosing depending on the value in field Class_name.

e.g. if Class_name = "Grass", change the blank Veg_Height field to "Short", if Class_name = "Trees", change the blank Veg_Height field to "Tall" etc.

Unfortunately, at the moment, I keep getting errors when I try to run this in model builder. Can anyone suggest any changes I could make?

Thanks 🙂

I also might try writing your if statement like this:


if row[0] == "Trees":
    row[1] = "Tall"

EDIT: Deleted first comment

Re: Bugs in script to populate an empty attribute field

Anonymous User — Sat, 11 Dec 2021 09:48:18 GMT

Original User: msayler

The '=' is used for assignment. Since you're doing a comparison, you need to use the 'equal to' operator instead, '=='.

i.e.

if row[0] == "Grass":
    row[1] = "Short"

Re: Bugs in script to populate an empty attribute field

Anonymous User — Sat, 11 Dec 2021 09:48:21 GMT

Original User: mzcoyle

As Amy and Matt pointed out, you are using the wrong equal operator for conditionals. Another option is to use a dictionary which can remove the need for conditionals completely, as well as making your code more easily extensible if you plan on adding additional classifications in the future.

curs_dict = {
    "Grass": "Short",
    "Trees": "Tall",
    "Urban": "N/A"}

for row in cursor:
    row[1] = curs_dict[row[0]]
    cursor.updateRow(row)

Re: Bugs in script to populate an empty attribute field

KerryThomas — Mon, 19 Aug 2013 17:06:01 GMT

Thanks so much!

Re: Bugs in script to populate an empty attribute field

Anonymous User — Mon, 19 Aug 2013 21:06:40 GMT

Original User: curtvprice

Here is a copy of my script.

[thread=48475]How to post Python code[/thread]