# List logic to combine and filter lists

**URL:** <https://forum.dynamobim.com/t/list-logic-to-combine-and-filter-lists/32701>\
**Category:** Lists-Logic\
**Created:** [February 27, 2019, 8:09am UTC](https://forum.dynamobim.com/t/list-logic-to-combine-and-filter-lists/32701 "2019-02-27T08:09:47Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sajithwetta](https://avatars.discourse-cdn.com/v4/letter/s/c6cbf5/32.png) [@sajithwetta](https://forum.dynamobim.com/u/sajithwetta)\
**Post date:** [February 27, 2019, 8:09am UTC](https://forum.dynamobim.com/t/list-logic-to-combine-and-filter-lists/32701/1 "2019-02-27T08:09:48Z")

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![t1](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/5/c/5c786fe0446d8c8d9814e8d653d4da2e52c23d95.png)  
I want to combine items from matching list indices to sub lists as shown in the middle code block and later make sub lists again if they include a common item ( list 0 is combined with list 2 as “a” is common to both).  
Is it possible to do this?

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**Author:** ![Tomasz](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/tomasz/32/66785_2.png) [@Tomasz](https://forum.dynamobim.com/u/Tomasz)\
**Post date:** [February 27, 2019, 8:38am UTC](https://forum.dynamobim.com/t/list-logic-to-combine-and-filter-lists/32701/2 "2019-02-27T08:38:59Z")

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It is possible.  
 ![Capture](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/b/e/be62038041fe86b736718fa9a1d61c2a4ba16cce.png)

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**Author:** ![sajithwetta](https://avatars.discourse-cdn.com/v4/letter/s/c6cbf5/32.png) [@sajithwetta](https://forum.dynamobim.com/u/sajithwetta)\
**Post date:** [February 27, 2019, 8:47am UTC](https://forum.dynamobim.com/t/list-logic-to-combine-and-filter-lists/32701/3 "2019-02-27T08:47:22Z")

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Thanks @Tomasz. Some great logic you got there.