# List.UniqueItems lacing

**URL:** <https://forum.dynamobim.com/t/list-uniqueitems-lacing/11230>\
**Category:** Lists-Logic\
**Created:** [April 23, 2017, 10:16am UTC](https://forum.dynamobim.com/t/list-uniqueitems-lacing/11230 "2017-04-23T10:16:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Ilya\_Kirichenko](https://avatars.discourse-cdn.com/v4/letter/i/f475e1/32.png) [@Ilya\_Kirichenko](https://forum.dynamobim.com/u/Ilya_Kirichenko)\
**Post date:** [April 23, 2017, 10:16am UTC](https://forum.dynamobim.com/t/list-uniqueitems-lacing/11230/1 "2017-04-23T10:16:36Z")

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hello everyone,  
how does lacing works in List.UniqueItems node? What is the logic behind it? I understand lacing logic for 2 lists in case of a “line by startpoint endpoint” node, but not here. So I tried an example that @Kulkul showed me in one of the cases.

I take an input list with two sublists:  
{{“A”,“B”,“C”,“A”},{1,2,2,1,1,1}};

Obviously if I use lacing shortest I get an expected identical list {{“A”,“B”,“C”,“A”},{1,2,2,1,1,1}};  
But when I use lacing longest the node works similar to as if I move down a level. So what is the logic behind lacing in this particular node?

![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/0/d/0d46b420026b030e9b15623508b7e76508ee85e3.jpg)

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**Author:** ![Enes\_Kaan\_Karabay](https://avatars.discourse-cdn.com/v4/letter/e/3ec8ea/32.png) [@Enes\_Kaan\_Karabay](https://forum.dynamobim.com/u/Enes_Kaan_Karabay)\
**Post date:** [April 23, 2017, 10:45am UTC](https://forum.dynamobim.com/t/list-uniqueitems-lacing/11230/2 "2017-04-23T10:45:57Z")

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not sure but;  
When you select lacing shortest;  
there is two element to check; first and second list. And these are different lists. This agrees with your example. 😃

When you use 2 equal list and add a number at the end.

![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/b/7/b7e42781c2e8ce13421a3a41fe9bdf337c166d86.PNG)

All collapse 😁  
Always take the first list.

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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:** [April 24, 2017, 1:26pm UTC](https://forum.dynamobim.com/t/list-uniqueitems-lacing/11230/3 "2017-04-24T13:26:54Z")

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@Ilya_Kirichenko Hope this gives an idea of the intended purpose of levels

 ![](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/9/b/9b8a09bbaea0a73f2aa671c6ea3bd8bf2b4bbc11.png)