topic Model Builder Iterator to calculate value of field in ModelBuilder Questions

Model Builder Iterator to calculate value of field

mattstutts — Thu, 10 Feb 2011 17:40:59 GMT

I don't use ModelBuilder too much and am trying to help someone w/this issue. I want to step through an attribute table and select each feature (currently trying the Iterate Feature Selection tool w/a group-by ID). These IDs are a variety of things (some are short strings like 30-11-222, some are GUIDS {A122......} but the field is type String.)

Simply, each time there is a new ID, copy that value and put it into another table that has an empty field called "ID".

This is just a small extract of a larger model, so it's sort of abstracted. But that's the basic idea of this section. Can't seem to get it to go. Originally, it would hang up on the Calculate Field b/c the 'value' coming from the iterator is type variant. I tried throwing in a 'Calculate Value' tool to change that to a string type and then running the Calculate Field but it doesn't like that either (some sort of syntax error: unexpected EOF while parsing (<string>, line 1).

Attaching a screen shot for now. Should be easier than this...

Re: Model Builder Iterator to calculate value of field

ChristopherDeRolph — Mon, 11 Apr 2011 18:51:22 GMT

I'm having this same issue Matt. Did you ever come up with a solution?

Thanks!

Chris

Re: Model Builder Iterator to calculate value of field

mattstutts — Mon, 11 Apr 2011 18:54:15 GMT

Nope. As usual, my questions go unanswered on this site. I had completely forgotten about it.

Re: Model Builder Iterator to calculate value of field

ChristopherDeRolph — Tue, 12 Apr 2011 15:29:34 GMT

Apparently this is a bug, but there is a workaround that works. Here's the email I got from ESRI tech support:

Hi Chris,

I have found bug ID #NIM055433. This bug recognizes that the Calculate Field tool fails when setting field value to iterator value when iterator uses a text field. The workaround is to put quotations around the %value%, such as "%value%". Please try this workaround and let me know the results.

Thanks for your time and patience!

Regards,

Evan B.

Re: Model Builder Iterator to calculate value of field

DarrenWiens2 — Sun, 12 Dec 2021 10:39:19 GMT

This code finds all unique IDs in a feature class, and sticks them into a new table.

import arcpy

input = "H:/GIS_Data/TEMP_GDB.gdb/feattoline" # feature class to iterate
gdb = "H:/GIS_Data/TEMP_GDB.gdb" #gdb or folder for your new table
table = "JunkTable"
tabpath = gdb + "/" + table

arcpy.CreateTable_management(gdb,table)

arcpy.AddField_management(tabpath,"ID","TEXT")

rows = arcpy.SearchCursor(input)

ids = []

for row in rows:
    if row.FID_polyfc not in ids:
        ids.append(row.FID_polyfc)

insrows = arcpy.InsertCursor(tabpath)

for id in ids:
    insrow = insrows.newRow()
    insrow.ID = id
    insrows.insertRow(insrow)

del row
del rows
del insrow
del insrows

PS - this is largely a community forum (ie. users answer questions on their own time), so don't be bitter if your question goes unanswered. Especially if it's not in the correct forum - this should be in 'Geoprocessing'.

Re: Model Builder Iterator to calculate value of field

JamesDuBois — Wed, 27 Aug 2014 20:11:56 GMT

Thanks for the assistance.. It turns out that I don't need to have a draw order field that starts at 0 every time for Tableau, it just needs to be sequential. So if I add a new field that mimics the FID field, it should do the trick.

Re: Model Builder Iterator to calculate value of field

Anonymous User — Tue, 03 May 2022 15:22:47 GMT

Thanks! This works and saved me a bunch of time!

Re: Model Builder Iterator to calculate value of field

Joseph_Kinyon — Sat, 17 Sep 2022 00:06:35 GMT

All,

I encountered this same problem in ModelBuilder in ArcGIS Pro 3.0 today ten years later and FYI the workaround still appears to do the job.

Joe