topic Re: Update attribute table using Arcpy in ArcAPI Questions

Update attribute table using Arcpy

Henryobaseki — Wed, 15 Nov 2017 17:18:53 GMT

Hi All,

This python code seems to work for updating two tables saw it online, with my low arcpy code skills

This seem to update the two tables

import arcpy
... from arcpy import env
... env.workspace = "C:\Users\L0505857\Data"
... print 'Processing...'
... fc = "Updated_subset.dbf"
... cursor = arcpy.da.SearchCursor(fc, ["RESID"])
... for row in cursor:
...     SQL_stat= "RESID = "+ str(row[0])
...     fc2 = "airports_old.dbf"
...     cursor2 = arcpy.da.SearchCursor(fc, ["FIELD_NAME"], SQL_stat)
...     for row2 in cursor2:
...         UpdatedValue = row2[0]
...         cursor3 = arcpy.da.UpdateCursor(fc2, ["FIELD_NAME"],SQL_stat)
...         for row3 in cursor3:
...             row3[0] = UpdatedValue
...             cursor3.updateRow(row3)
... del row
... del cursor
... del row2
... del cursor2
... del row3
... del cursor3
...
... print "Done"

thisSQL_stat line ---SQL_stat= "RESID = "+ str(row[0])

converts the unique ID field "RESID Field" to string.

How do I remove the str for a another table in which the RESID field is already a string and not an interger field?

SQL_stat= "RESID = "+ (row[0])

tried the line above without the str, I m getting errors.

Thanks for your help

Re: Update attribute table using Arcpy

JoshuaBixby — Wed, 15 Nov 2017 17:51:54 GMT

Sharing with https://community.esri.com/community/developers/gis-developers/python?sr=search&searchId=b4b17813-e9e5-48eb-89bc-3ea7c4ab364e&searchIndex=1‌ since this is an ArcPy question.

Re: Update attribute table using Arcpy

DarrenWiens2 — Wed, 15 Nov 2017 18:15:20 GMT

Include the full error message. There shouldn't be a problem trying to cast an existing string to a string (e.g. str("my_string")).

Re: Update attribute table using Arcpy

RandyBurton — Sun, 12 Dec 2021 09:47:10 GMT

Since you are creating an SQL where clause, you may need the string in quotes for comparison. It may be helpful to use something like:

>>> row =  ( 123, "hello")
>>> sql = "RESID = {}".format(row[0]) # for numbers
>>> sql
'RESID = 123'
>>> sql = "RESID = '{}'".format(row[1]) # for strings
>>> sql
"RESID = 'hello'"‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Update attribute table using Arcpy

RebeccaStrauch__GISP — Wed, 15 Nov 2017 19:39:26 GMT

It would help if you edit you post and post the code using https://community.esri.com/people/curtvprice/blog/2014/09/25/posting-code-blocks-in-the-new-geonet?sr=search&searchId=a8d8fb1f-5622-4402-bb65-833b791e21e9&searchIndex=6‌ or /blogs/dan_patterson/2016/08/14/script-formatting?sr=search&searchId=a483b6b2-88cf-4672-bb4a-703edf98fba9&searchIndex=1‌

What I see right off in what you post, assuming the spacing is how you are trying to use it, is all the lines that are indented (line 2 down) shouldn't be, until you get to the "for row in cursor:" then some of the lines below that might need to be. I did not look at the entire code, but fixing the indentation is probably the first step (again, assuming the spacing shown is what you are trying to use).

Re: Update attribute table using Arcpy

Henryobaseki — Thu, 16 Nov 2017 09:16:24 GMT

Hi Darren,

>>> import arcpy

... from arcpy import env

... env.workspace = "C:\Data"

... print 'Processing...'

... fc = "Updated_subset.dbf"

... cursor = arcpy.da.SearchCursor(fc, ["RESID"])

... for row in cursor:

... SQL_stat= "RESID = "+ str(row[0])

... fc2 = "airports_old.dbf"

... cursor2 = arcpy.da.SearchCursor(fc, ["Regional_s"], SQL_stat)

... for row2 in cursor2:

... UpdatedValue = row2[0]

... cursor3 = arcpy.da.UpdateCursor(fc2, ["Regional_s"],SQL_stat)

... for row3 in cursor3:

... row3[0] = UpdatedValue

... cursor3.updateRow(row3)

... del row

... del cursor

... del row2

... del cursor2

... del row3

... del cursor3

...

... print "Done"

...

Processing...

Runtime error

Traceback (most recent call last):

File "<string>", line 11, in <module>

RuntimeError: A column was specified that does not exist.

see the runtime error

Thanks