topic Re: Accessing "derived output" values of Append tool in Python Questions

Accessing "derived output" values of Append tool

Sfortunatamente — Thu, 06 Jun 2024 14:07:27 GMT

I have a simple script which uses the Append gp tool with the option to update existing records (upsert). I am trying to access derived output parameters "appended_row_count" and "updated_row_count". Are these elements of the list? I am getting The index 1 is out of range error.

When I check the Get count gp tool output parameter ("row_count") it is being accessed as the first element of the list. It does not seem to be working for me for the other tool.

How to get these two long integer values in the py script?

Thanks.

Re: Accessing "derived output" values of Append tool

DanPatterson — Thu, 06 Jun 2024 17:01:36 GMT

not sure I follow, but anyway, the first element of a python list is 0, if index 1 is being queried and doesn't exist, that is why you are getting the error

another possibility is that a list is being returned (index 0) which may contain more than 1 element eg 0 and 1) so you would have to get the list then index into it

Re: Accessing "derived output" values of Append tool

Sfortunatamente — Thu, 06 Jun 2024 18:26:50 GMT

Yeah, I put the question is a quite complicated way. Look at the screenshot.

the code is:

loaded = arcpy.management.Append(
inputs=inputLayer,
target=destTable,
schema_type="NO_TEST",
field_mapping=None,
subtype="",
expression="",
match_fields="keyfield keyfield",
update_geometry="UPDATE_GEOMETRY"
)

it appends the data. If you look at the tool description in the section of the Derived Output you see three parameters. I do not know how to get a second and third long integer value. When printing "loaded" I get only path to target feature class.

Re: Accessing "derived output" values of Append tool

Sfortunatamente — Thu, 06 Jun 2024 18:49:52 GMT

Sorry, my fault. I have Pro 3.2. Three parameters in the Append tool are available in version 3.3..

Re: Accessing "derived output" values of Append tool

JonathanMurphy2 — Thu, 05 Dec 2024 16:30:03 GMT

You can get the output like this,

# Print derived output and messages print("Derived Output (Target Layer):", append[0]) # The first element is the target layer path print("Messages:") for message in append.getMessages().splitlines(): print(message)

Re: Accessing "derived output" values of Append tool

JonathanMurphy2 — Thu, 05 Dec 2024 16:32:48 GMT

Whoops, hit enter too quickly. Updated to use the variable you set for the append function,

# Print derived output and messages print("Derived Output (Target Layer):", loaded[0]) # The first element is the target layer path print("Messages:") for message in lloaded.getMessages().splitlines(): print(message)

Re: Accessing "derived output" values of Append tool

D_Atkins — Wed, 17 Sep 2025 12:40:19 GMT

I don't think the messages output is a reliable solution to accessing those counts values...

We stumbled onto this thread and feel the need to reiterate the question: how do we reliably access the LONG values promised by the documentation (appended_row_count and updated_row_count) with ArcPy?

Re: Accessing "derived output" values of Append tool

NicolasDELAVAL66 — Thu, 04 Dec 2025 13:22:20 GMT

result = arcpy.management.Append(............)

result.getOutput(0) => Updated Target Dataset

result.getOutput(1) => Appended Row Count

result.getOutput(2) => Updated Row Count