# Help - Give elements sequential numbers with identical elements getting the same number?

**URL:** <https://forum.dynamobim.com/t/help-give-elements-sequential-numbers-with-identical-elements-getting-the-same-number/89908>\
**Category:** Revit\
**Tags:** dynamo\
**Created:** [May 22, 2023, 7:31pm UTC](https://forum.dynamobim.com/t/help-give-elements-sequential-numbers-with-identical-elements-getting-the-same-number/89908 "2023-05-22T19:31:46Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![bennorth60](https://avatars.discourse-cdn.com/v4/letter/b/919ad9/32.png) [@bennorth60](https://forum.dynamobim.com/u/bennorth60)\
**Post date:** [May 22, 2023, 7:31pm UTC](https://forum.dynamobim.com/t/help-give-elements-sequential-numbers-with-identical-elements-getting-the-same-number/89908/1 "2023-05-22T19:31:46Z")

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I want to give each pipe fitting a sequential number starting 14/ but only those with the material parameter “Ductile Iron”. The filter and numbering works in isolation but cant seem to get dynamo to give identical items the same number?

Any advice apprecitated…  
[PF Numbering.dyn](https://forum.dynamobim.com/uploads/short-url/xIL5neVI07GrymhUTi6hejmdMZ7.dyn) (65.9 KB)

 ![PF Numbering_2023-05-22_08-21-43](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/8/2/8223a5106ae4be8ef977f5617887112a0653e73e.png)

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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:** [May 22, 2023, 8:57pm UTC](https://forum.dynamobim.com/t/help-give-elements-sequential-numbers-with-identical-elements-getting-the-same-number/89908/2 "2023-05-22T20:57:30Z")

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You’ll need to take another screenshot that’s legible but you should be able to group by key to group identical items and then number based on unique keys instead of unique items.

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**Author:** ![bennorth60](https://avatars.discourse-cdn.com/v4/letter/b/919ad9/32.png) [@bennorth60](https://forum.dynamobim.com/u/bennorth60)\
**Post date:** [May 22, 2023, 9:15pm UTC](https://forum.dynamobim.com/t/help-give-elements-sequential-numbers-with-identical-elements-getting-the-same-number/89908/3 "2023-05-22T21:15:16Z")

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![PF Numbering_2023-05-22_08-21-43](https://us1.discourse-cdn.com/flex022/uploads/dynamobim/original/3X/3/3/3334babd7fdc30afa1522fa3871296f06c6142fd.png)

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<div class="post-metadata">

**Author:** ![bennorth60](https://avatars.discourse-cdn.com/v4/letter/b/919ad9/32.png) [@bennorth60](https://forum.dynamobim.com/u/bennorth60)\
**Post date:** [May 22, 2023, 9:16pm UTC](https://forum.dynamobim.com/t/help-give-elements-sequential-numbers-with-identical-elements-getting-the-same-number/89908/4 "2023-05-22T21:16:26Z")

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Hi @Nick_Boyts

Thanks for the reply, hopefull this is legible now, can you elaborate pls?