# Remove Empty List with List.Clean

**URL:** <https://forum.dynamobim.com/t/remove-empty-list-with-list-clean/37686>\
**Category:** Revit\
**Tags:** dynamo\
**Created:** [June 27, 2019, 6:23pm UTC](https://forum.dynamobim.com/t/remove-empty-list-with-list-clean/37686 "2019-06-27T18:23:25Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![chernandez](https://avatars.discourse-cdn.com/v4/letter/c/c67d28/32.png) [@chernandez](https://forum.dynamobim.com/u/chernandez)\
**Post date:** [June 27, 2019, 6:23pm UTC](https://forum.dynamobim.com/t/remove-empty-list-with-list-clean/37686/1 "2019-06-27T18:23:25Z")

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Trying to remove this empty list in my Room.FinishBoundary but cant seem to get it cleaned out so it will run through all my rooms what as I missing?  
 ![clean](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/c/a/ca35595188efc52b24600697011788bcb24ef34a.png)

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**Author:** ![SeanP](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/seanp/32/42560_2.png) [@SeanP](https://forum.dynamobim.com/u/SeanP)\
**Post date:** [June 27, 2019, 6:26pm UTC](https://forum.dynamobim.com/t/remove-empty-list-with-list-clean/37686/2 "2019-06-27T18:26:39Z")

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Use a List.IsEmpty node and a FilterByBooleanMask node to get ride of it

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**Author:** ![Nick\_Boyts](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/nick_boyts/32/76313_2.png) [@Nick\_Boyts](https://forum.dynamobim.com/u/Nick_Boyts)\
**Post date:** [June 27, 2019, 8:17pm UTC](https://forum.dynamobim.com/t/remove-empty-list-with-list-clean/37686/3 "2019-06-27T20:17:22Z")

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You’re cleaning the list of Rooms, not their boundaries. You may have unplaced rooms that are giving you empty lists. Run the List.Clean node after you’ve gotten boundaries. However, if you need to filter out the rooms without boundaries later on I would follow @SeanP’s advice and use a mask.