# How to increase a list into a list of lists from unique items?

**URL:** <https://forum.dynamobim.com/t/how-to-increase-a-list-into-a-list-of-lists-from-unique-items/10537>\
**Category:** Uncategorized\
**Created:** [March 23, 2017, 5:02pm UTC](https://forum.dynamobim.com/t/how-to-increase-a-list-into-a-list-of-lists-from-unique-items/10537 "2017-03-23T17:02:57Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mix](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@mix](https://forum.dynamobim.com/u/mix)\
**Post date:** [March 23, 2017, 5:02pm UTC](https://forum.dynamobim.com/t/how-to-increase-a-list-into-a-list-of-lists-from-unique-items/10537/1 "2017-03-23T17:02:57Z")

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hello, I am trying to find out how many of each type of pipe fitting I have in my system. I have a list of all the pipe fitting sizes, but I dont know how to break the list down into sublists so that each sublist has all the same size fittings in it. Does that make sense? I looked at the definition of unique items an sublists, but unique items will get rid of all but one of each and I want the total count of each and sublists, doesnt break it down by value of the line item but only by a preset input which wont work either. Please advise. Thanks!

 ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/5/6/569d54a1e95403defb87c1f61276749082ed7d37.png)

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**Author:** ![mix](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@mix](https://forum.dynamobim.com/u/mix)\
**Post date:** [March 23, 2017, 5:14pm UTC](https://forum.dynamobim.com/t/how-to-increase-a-list-into-a-list-of-lists-from-unique-items/10537/2 "2017-03-23T17:14:21Z")

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Ok I actually found this node from clockwork that does this for me. But now how do I get the total length of each pipe size into my list of size and count of pipes?

 ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/7/0/70a35a05405bd6080f489d177bba7fe8953a1e34.png)

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**Author:** ![Vikram\_Subbaiah](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.dynamobim.com/vikram_subbaiah/32/50797_2.png) [@Vikram\_Subbaiah](https://forum.dynamobim.com/u/Vikram_Subbaiah)\
**Post date:** [March 23, 2017, 7:29pm UTC](https://forum.dynamobim.com/t/how-to-increase-a-list-into-a-list-of-lists-from-unique-items/10537/3 "2017-03-23T19:29:35Z")

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@mix Seems like _List.GroupByKey_ should serve your purpose

 ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/7/f/7f32b7277db518bbb653a6d9d39d6dbdc0ddc208.png)