https://community.appian.com/discussions/f/process/21817/how-to-implement-a-set-data-structure-in-appianHello, I would like to implement a &quot;set&quot; data structure in appian. My use case prefers a &quot;set&quot; data structure as opposed to a list or dictionaries, because a set only contains unique values, or in my use case, unique sets. I tried to search in theen-USTelligent Community 12https://community.appian.com/thread/85471?ContentTypeID=1Sat, 04 Sep 2021 11:02:19 GMTd3a83456-d57b-489c-a84c-4e8267bb592a:95fe03f1-053c-453b-81b5-cdb8b4f24390Stefan Helzle<p>What is the purpose? I mean, the functional requirement.</p><div style="clear:both;"></div>https://community.appian.com/thread/85467?ContentTypeID=1Fri, 03 Sep 2021 16:19:36 GMTd3a83456-d57b-489c-a84c-4e8267bb592a:7f3a1a98-72be-4345-ac77-659dd4202b8dJosh<p>I don&#39;t think there is a set data structure per-se, but you could implement one using a simple rule that takes in your set and the values you are trying to insert (you may need to augment the example for more robust error handling and edge cases) and returns the resulting set:</p> <p><pre class="ui-code" data-mode="text">union( ri!existingSet, ri!dataToInsert )</pre></p><div style="clear:both;"></div>