# How to select all rooms without one room

**URL:** <https://forum.dynamobim.com/t/how-to-select-all-rooms-without-one-room/38342>\
**Category:** Revit\
**Tags:** revit\
**Created:** [July 16, 2019, 9:02am UTC](https://forum.dynamobim.com/t/how-to-select-all-rooms-without-one-room/38342 "2019-07-16T09:02:19Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![ka-wai.liu9ECQM](https://avatars.discourse-cdn.com/v4/letter/k/f05b48/32.png) [@ka-wai.liu9ECQM](https://forum.dynamobim.com/u/ka-wai.liu9ECQM)\
**Post date:** [July 16, 2019, 9:02am UTC](https://forum.dynamobim.com/t/how-to-select-all-rooms-without-one-room/38342/1 "2019-07-16T09:02:19Z")

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Hi,

I am beginner of using dynamo. I want to filter out all plant rooms which areas are not exceed 100m². I can select the rooms as you see, but how to select other rooms without these rooms?

 ![Capture1](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/6/3/63cfdad4e9ed9296a6697ca08c4ed499861040ad.png)

thank you

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**Author:** ![Jan\_Secnik](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/jan_secnik/32/55692_2.png) [@Jan\_Secnik](https://forum.dynamobim.com/u/Jan_Secnik)\
**Post date:** [July 16, 2019, 11:14am UTC](https://forum.dynamobim.com/t/how-to-select-all-rooms-without-one-room/38342/2 "2019-07-16T11:14:24Z")

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If I understand correcty, you want to get all the rooms - PLANT ROOM?

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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:** [July 16, 2019, 2:19pm UTC](https://forum.dynamobim.com/t/how-to-select-all-rooms-without-one-room/38342/3 "2019-07-16T14:19:10Z")

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If you know the room name the quickest and easiest thing to do would just be filter out the room with that name.

You can also join the lists of rooms that are _not_ your selected room.

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**Author:** ![Ren\_Rainville](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/ren_rainville/32/13298_2.png) [@Ren\_Rainville](https://forum.dynamobim.com/u/Ren_Rainville)\
**Post date:** [July 16, 2019, 2:46pm UTC](https://forum.dynamobim.com/t/how-to-select-all-rooms-without-one-room/38342/4 "2019-07-16T14:46:18Z")

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you can take the entire list of rooms, search the room name you want to remove, get the index of that room element and use RemoveItemAtIndex and the list will be all OTHER rooms than the one you don’t want.  
 ![2019-07-16%2007_45_35-Dynamo](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/c/9/c93fd7cd11bc19a9c415227a728b262301e6b455.jpeg)

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**Author:** ![Mark.Ackerley](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/mark.ackerley/32/79310_2.png) [@Mark.Ackerley](https://forum.dynamobim.com/u/Mark.Ackerley)\
**Post date:** [July 16, 2019, 9:03pm UTC](https://forum.dynamobim.com/t/how-to-select-all-rooms-without-one-room/38342/5 "2019-07-16T21:03:17Z")

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Another option…

List.SetDifference with your list as the input 1 and your room to be removed as input 2

Hope that’s of interest,

Mark

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**Author:** ![Marcel\_Rijsmus](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/marcel_rijsmus/32/8539_2.png) [@Marcel\_Rijsmus](https://forum.dynamobim.com/u/Marcel_Rijsmus)\
**Post date:** [July 16, 2019, 9:21pm UTC](https://forum.dynamobim.com/t/how-to-select-all-rooms-without-one-room/38342/6 "2019-07-16T21:21:30Z")

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or filter by boolean mask and take the OUT option after filtering (eg. doesn’t comply to the rule you set)

 ![image](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/9/e/9e8ba2893bd997043c40cb064d62c1779368b8e9.png)

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**Author:** ![ka-wai.liu9ECQM](https://avatars.discourse-cdn.com/v4/letter/k/f05b48/32.png) [@ka-wai.liu9ECQM](https://forum.dynamobim.com/u/ka-wai.liu9ECQM)\
**Post date:** [July 17, 2019, 1:58am UTC](https://forum.dynamobim.com/t/how-to-select-all-rooms-without-one-room/38342/7 "2019-07-17T01:58:21Z")

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I want to filet out all plant rooms which areas are exceed 100m².

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**Author:** ![ka-wai.liu9ECQM](https://avatars.discourse-cdn.com/v4/letter/k/f05b48/32.png) [@ka-wai.liu9ECQM](https://forum.dynamobim.com/u/ka-wai.liu9ECQM)\
**Post date:** [July 17, 2019, 4:42am UTC](https://forum.dynamobim.com/t/how-to-select-all-rooms-without-one-room/38342/8 "2019-07-17T04:42:14Z")

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I did it, thank you Mark and Guys.  
 ![Capture](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/3/0/30d6f34eb664d8ee5e95757ec5d4ea801571bd43.png)