topic Re: Iterator values start at 1? in Geoprocessing Questions

Iterator values start at 1?

TomBonnot — Wed, 02 Mar 2011 15:59:29 GMT

Hi,
I have been trying to use an iterate field value tool in my models. Each iteration I want to use the value in an SQL expression. But the first value returned from the iterator is always a "1", which is not in my field values at all. Because there is no 1, the tool using the expression always crashes. Why does the iterator generically start with 1 and not my first field value?

Thanks,
Tom

Re: Iterator values start at 1?

ChristopherDeRolph — Tue, 15 Mar 2011 18:32:58 GMT

I am experiencing this same issue. Anyone have an answer for this yet?

Thanks!

Chris

Re: Iterator values start at 1?

BBicking1 — Wed, 16 Mar 2011 13:53:09 GMT

I am experiencing this same issue. Anyone have an answer for this yet?

Thanks!

Chris

Hi Tom,

Please attach your model with a small sample of your data.

Barbara Bicking
Geoprocessing Team

Re: Iterator values start at 1?

GabeMarcello — Thu, 17 Mar 2011 13:13:17 GMT

Same issue here.

I have 17 division names in a string field [Division].

I have 'Iterate Field Values' iterator with SQL Expression selected as data type. I want the model to take each unique value in [Division] and use it in the next tool 'Select Layer By Attribute' as the expression [Division]='%'

I could be wrong, but Isn't this how SQL Expression in this iterator is supposed to work?

I also tried an inline variable in my 'Select Layer By Attribute' expression: [Division]='%Value%' and set the Iterator data type back to string. The selection came out: [Division]='1'. When really it should be something like [Division]='Lakeshore'

I get the same generic Value=1 for every different type of field in my feature class, no matter if it is string, long, short, float, double, etc. Even if the iterator is outputting the number of iterations instead of the actual value it should still show me the number of unique values (in the case of [Division], 17) instead of 1. But I thought the iterator was supposed to output the actual unique value of the field specified?

Re: Iterator values start at 1?

BBicking1 — Thu, 17 Mar 2011 14:55:27 GMT

Same issue here.

I have 17 division names in a string field [Division].

I have 'Iterate Field Values' iterator with SQL Expression selected as data type. I want the model to take each unique value in [Division] and use it in the next tool 'Select Layer By Attribute' as the expression [Division]='%'

I could be wrong, but Isn't this how SQL Expression in this iterator is supposed to work?

I also tried an inline variable in my 'Select Layer By Attribute' expression: [Division]='%Value%' and set the Iterator data type back to string. The selection came out: [Division]='1'. When really it should be something like [Division]='Lakeshore'

I get the same generic Value=1 for every different type of field in my feature class, no matter if it is string, long, short, float, double, etc. Even if the iterator is outputting the number of iterations instead of the actual value it should still show me the number of unique values (in the case of [Division], 17) instead of 1. But I thought the iterator was supposed to output the actual unique value of the field specified?

Hi Gabe,

without having a copy of your model, I can't tell why you get what you get.

Barbara

Re: Iterator values start at 1?

GabeMarcello — Thu, 17 Mar 2011 15:18:19 GMT

Hi Gabe,

without having a copy of your model, I can't tell why you get what you get.

Barbara

Will this attachment suffice?

Re: Iterator values start at 1?

BBicking1 — Fri, 18 Mar 2011 14:20:46 GMT

Will this attachment suffice?

Hi Gabe,

Thanks so attaching the model.
Your first Select Layer by Attribute uses the output, i.e., Value from Iterate Field Values, yet the iterator has not yet run.

Also, do you intend to iterate every process every time the iterator outputs another Value?

Barbara Bicking

Re: Iterator values start at 1?

GabeMarcello — Fri, 18 Mar 2011 16:40:25 GMT

Hi Gabe,

Thanks so attaching the model.
Your first Select Layer by Attribute uses the output, i.e., Value from Iterate Field Values, yet the iterator has not yet run.

Also, do you intend to iterate every process every time the iterator outputs another Value?

Barbara Bicking

Barbara,

I guess I don't understand. I want the entire model to run each time the Iterator selects a new unique value in the specified feature class field. Where does the iterator have to be placed in the model for it to run?

Re: Iterator values start at 1?

MarkWheeler — Mon, 21 Mar 2011 19:56:25 GMT

Was there ever a resolution to this issue?

I've got the exact same problem. No matter what the data type of the field, the resulting value of VALUE is 1. I have an input table with a 'Usercode' field of string values. According to Help, the iteration should select every unique value in the "Usercode' and pass that string value on.

Re: Iterator values start at 1?

GabeMarcello — Mon, 21 Mar 2011 23:03:31 GMT

Was there ever a resolution to this issue?

I've got the exact same problem. No matter what the data type of the field, the resulting value of VALUE is 1. I have an input table with a 'Usercode' field of string values. According to Help, the iteration should select every unique value in the "Usercode' and pass that string value on.

I stumbled upon the solution when I decided to just let my model run to see what happened. Apparently, the first iteration used the value '1' and all my selections were empty because of this. After the model finished for the value '1' it started to iterate through the actual values. Worked perfectly!

Re: Iterator values start at 1?

BBicking1 — Tue, 22 Mar 2011 15:30:01 GMT

I stumbled upon the solution when I decided to just let my model run to see what happened. Apparently, the first iteration used the value '1' and all my selections were empty because of this. After the model finished for the value '1' it started to iterate through the actual values. Worked perfectly!

Hi Gabe,

you can eliminate the initial run by constructing your model such that the iterator is the first process to run, thus it gets initiallized to the value you want.
As I said above, now your first process runs and the iterator hasn't done anything and therefore it uses the default value 1.
I asked if you want to iterate the entire model because of where you placed the iterator in the model, yet wanted the output from the iterator used in your model's first process.

Barbara Bicking

Re: Iterator values start at 1?

JordanChamberlin — Sun, 10 Apr 2011 17:16:23 GMT

you can eliminate the initial run by constructing your model such that the iterator is the first process to run, thus it gets initiallized to the value you want.

HOW do you do this, please?

Thanks!

Re: Iterator values start at 1?

HeatherCarlos — Wed, 21 Sep 2011 16:10:14 GMT

Hello,
I'm having a similar problem, but I have the precondition set. I'm using Iterate Field Values and then I use the output as in-line variable substitution in Get Field Value. However, Get Field Value won't run because the default of the Iterator is 1 and I get the error "Field 1 does not exist within table".

You can see in the attachment, Get Field Value is "not ready-to-run" - even once I run the iterator (and the iterator is no longer 1), the state of Get Field Value doesn't change and therefore it doesn't run. I can manually trick it into Ready to Run state (by running the iterator and then opening, editing, cancelling the edit and closing Get Field Value), but since the iterator has already run, that doesn't help and once I reset it, it turns white.

Re: Iterator values start at 1?

ShitijMehta — Wed, 21 Sep 2011 20:19:18 GMT

HI HCarlos,

Couple of things need some clarification in your model.

1. This is what Get Field Value tool does - The Get Field Value tool gets the value of the first row of a table for the specified field.

2. Why are you iterating over field values using an iterator? This is what Iterate Field Value iterator does - Iterates over each value in a field. So you are iterating over a field value row by row.

3. How and Why are you using the output of the iterator which is the value of the field in the get field value tool? Get Field Value tool will only get the value of a first row of a field. So how are you using the output of the iterator as inline variable substitution?

4. What do you want to do through this model?

Re: Iterator values start at 1?

CarelKotze — Fri, 08 Dec 2017 20:54:49 GMT

I was wondering if anyone has figured out a work around for this issue. I am running into the exact same problem.

A simple model - Iterate field value (Name)- use the string output value to run a Make Feature Layer (Name =%Value%)

It will run and immediately stop with the error message Name = 1 does not exist. Examining the model after it ran, it shows that the Value output for Iterate field value now equals 1 even though that value does not exist in the data.

I even tried running the Iterate field value by itself after this happen and it gave me the same result Value = 1.

A this point I closed everything down, opened it back up, ran the same model with no changes and it worked, once, and then went back the Value = 1 issue.

Any help with this would be appreciated.

Thanks

Re: Iterator values start at 1?

ShitijMehta — Fri, 08 Dec 2017 21:17:19 GMT

Hi, Carel Kotze

Is it possible to share your model and your data sample?
The default output of the iterator is 1 because, before it has run there is no way to know what the value will be. Especially when you are making generic models with undefined variable values or data types there is no way to connect the output of the iterator to the downstream tools if it has absolutely no information.
If I could see the model snapshot with the tool dialog of the tools both iterator and the Make Feature Layer that would help solve this. I am wondering if the SQL expression parameter is somehow set to a value of 1.

Thanks!

Shitij

Re: Iterator values start at 1?

CarelKotze — Sat, 09 Dec 2017 00:12:12 GMT

Here's an image of the model, table and parameters.

What bothers me is the inconsistency of the model, it will run fine one moment and then switch to the problem I have mentioned above, without me changing anything.

The way I managed to make the model work the last time is to change the Input value from the drop down option (the layer is in my table of contents) to the hard drive location using the browse button.

That fixed the problem without me having to change anything else in the model.

Re: Iterator values start at 1?

CarelKotze — Sat, 09 Dec 2017 00:13:34 GMT

The image

Re: Iterator values start at 1?

ShitijMehta — Mon, 11 Dec 2017 20:45:39 GMT

What you are describing is an inconsistent behavior and a bug with reading a layer, unfortunately i am unable to reproduce it with the current version. Which ArcMap version do you have?

Re: Iterator values start at 1?

CarelKotze — Thu, 14 Dec 2017 20:12:13 GMT

I am using ArcGIS 10.5.1