# Dynamo bug? - 2 identical lists, provide different outputs - how possible? **URL:** \ **Category:** Packages\ **Created:** [November 24, 2015, 2:42pm UTC](https://forum.dynamobim.com/t/dynamo-bug-2-identical-lists-provide-different-outputs-how-possible/2584 "2015-11-24T14:42:41Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Luigi\_Coletta](https://avatars.discourse-cdn.com/v4/letter/l/82dd89/32.png) [@Luigi\_Coletta](https://forum.dynamobim.com/u/Luigi_Coletta)\ **Post date:** [November 24, 2015, 2:42pm UTC](https://forum.dynamobim.com/t/dynamo-bug-2-identical-lists-provide-different-outputs-how-possible/2584/1 "2015-11-24T14:42:41Z")
Hello…why would a list, seemingly identical, would cause the same node to behave differently? When I use a list of levels from a list.map node the floor get re-created at each run…but if the same list created with list.create node, the floor doesn’t get re-created. First question…why would the same list provide different outcomes? how can I use the List.Map sequence (or similar?) and not have the floor re-created each time? is this a bug? or is it how Revit’s API deals with where how the level list is created? Seems odd that the outcome is different. Below is the Dynamo script…and if you want, just a simple revit file with 2 levels and 2 rooms. thank you in advance! \Dynamo Script\ - [**Community Help - Automatic with ListMap**](http://dynamobim.org/wp-content/uploads/forum-assets/luigicoletta/11/24/Community-Help-Automatic-with-ListMap.dyn)   [Revit basic file - PROJECT COMMUNITY - TEST](http://dynamobim.org/wp-content/uploads/forum-assets/luigicoletta/11/24/PROJECT-COMMUNITY-TEST.rvt) ![Same list different results](http://dynamobim.org/wp-content/uploads/forum-assets/luigicoletta/11/24/Same-list-different-results1.jpg) ---
**Author:** ![Luigi\_Coletta](https://avatars.discourse-cdn.com/v4/letter/l/82dd89/32.png) [@Luigi\_Coletta](https://forum.dynamobim.com/u/Luigi_Coletta)\ **Post date:** [November 24, 2015, 3:09pm UTC](https://forum.dynamobim.com/t/dynamo-bug-2-identical-lists-provide-different-outputs-how-possible/2584/2 "2015-11-24T15:09:23Z")
So…I’m trying to remember why I ended not using the “elements” output from the lunchbox Room Element Collector…there was something weird with it a few days ago…but now the element works for me in the nodes I show. For some reason if I get the list of elements from the all elements of category node…it causes the re-creation of the floors…again, not sure why…but it does. I can now make it work with the custom node…but still don’t know why the 2 lists would create a different output. ---
**Author:** ![Michael\_Kirschner](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/michael_kirschner/32/237_2.png) [@Michael\_Kirschner](https://forum.dynamobim.com/u/Michael_Kirschner)\ **Post date:** [November 26, 2015, 2:51am UTC](https://forum.dynamobim.com/t/dynamo-bug-2-identical-lists-provide-different-outputs-how-possible/2584/3 "2015-11-26T02:51:25Z")
it’s tricky, can you clarify if you are still seeing this? I think the issue is the AllElementsOfCategory node, just a guess, it’s possible that after creation of a floor, this element collector node is firing again, causing a recreation of floors, but it should stop after 1 round of inputs being the same on the floor element constructor, - we may not be detecting outline inputs as “the same” correctly. ---
**Author:** ![Luigi\_Coletta](https://avatars.discourse-cdn.com/v4/letter/l/82dd89/32.png) [@Luigi\_Coletta](https://forum.dynamobim.com/u/Luigi_Coletta)\ **Post date:** [November 30, 2015, 8:33am UTC](https://forum.dynamobim.com/t/dynamo-bug-2-identical-lists-provide-different-outputs-how-possible/2584/4 "2015-11-30T08:33:31Z")
Hello Michael, If I use the All ElementsOfCategory node it goes to infinite loop…the weird thing is that if I manually run it the level ID and the floor ID remain the same…so no re-creation…but when I run it automatically, it will constantly re-create it and go into an infinite loop…I know this because I connected a write to excel node and noticed the ID of the floors constantly change. So yes, it still happens with the same node. When I use the lunchbox custom node for collecting the elements then it works…weird thing is that if I run it manually it will re-create the floor each time I run it…but if I run it automatically, it won’t go into infinite loop…essentially the opposite…but at least I get the results I need. ![infinite loop](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/2X/5/5808c46a0a47d6fa491f1b8c87ffee05b50488e8.jpg)