Is it possible to use the contents of a single column csv file to limit the list of acceptable inputs for a tool in a python toolbox? I'm aware that I can use the code below to achieve my requirements, but the list I need often varies outside of ArcGIS and outside of my control and therefore the code would need regular updates.

options1 = [1, 2] param0.filter.type = "Value List" param0.filter.list = options1


Try opening the csv and loading the values into a list.

import csv

param0.filter.type = "Value List"
with open('c:/pythontools/file.csv', 'rb') as f:
    reader = csv.reader(f)
    param0.filter.list = [item for sublist in list(reader) for item in sublist]

Edit: By default, the list(reader) returns a list, so we need to flatten the list of lists into a single list.

You will also want to fully specify the path of the csv file to avoid any path issues.

This post on StackOverflow has more details.

  • Thanks for your help Richard. Using the code above isn't working for me. I'm ending up with a little red cross on the tool's icon. Trying to run it produces an error box saying "Unable to execute the selected tool.". – davehughes87 Sep 30 '16 at 12:12
  • I should point out that if I manually specify the options list, the tool works correctly, so the issue is being caused by the csv code. – davehughes87 Sep 30 '16 at 12:31
  • @davehughes87, can you give the error message in full? – fatih_dur Sep 30 '16 at 12:44
  • @davehughes87 I forgot the list(reader) returns a list even if there's just a single entry. As the filter.list needs a flattened list, we need to sample out the values. See updated code. – Richard Morgan Sep 30 '16 at 12:47
  • The tool runs fine without using the csv code. Adding the csv code means the tool is not placed in the correct folder and instead shows up with a red cross bit.ly/2cQvvKD. ArcMap suggests the syntax of the toolbox is correct and will still run all other tools. Attempting to run this tool results in the following window. bit.ly/2dpZBpi – davehughes87 Sep 30 '16 at 12:48

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