Element indexes inside nested list

Hello everyone,
I’m working on my master thesis, and im new to Dynamo. I could solve 90% of my doubts in this forum due to other people questions, but i couldnt find something that solves the following problem. Since it has been a while that I’have been trying to find a solution finally decided to ask here.
I have a list of elements (list 1), and I want for each element of that list, to scan a second list (list 2), nested @L2, and find the index of each element of the list 1 that falls into the nested list 2. (every item of list 1 falls into list 2 since they are the same elements) From that index that i find for that element, I’d like to associate another element with the same index that is coming from a third list (list 3). So, to be claire: in list 3 are contained all the panels, in the nested list 2 all connected elements under each panel, anche in list 1 all elements.
So, at the end of the story, for each element in list 1, associate its panel from list 3.

I tried a solution with “index of” and “list lace longest” nodes but it works only with the first element of list 1

I’would really appreciate if someone could help me.
(sorry for my english, it’s not very good)


to be clear, why do you need to connect list 1( the element ) with list 3 ( panels ) ? where it have already associated in list 2 ?

another question , what do you mean with associate list 1 with 3 ? what the result should be ?

so you just need fire alarm circuits ?

Yes, i need only fire alarm circuits.
So, the aim of this work is to fill a shared parameter for the “fire alarm device schedule”, because i need to know, which device is connected to which panel.
The shared parameter should be filled like this:
[Device]_ [device number]_ [panel]_ [panel number]
The only thing i have been stuck, is how to associate panel directly to the device… For this reason in need to go from list 1 to list 3

i think this will help you , if not give me a feedback,

Thank you for your reply,
unfortunately didnt work, since in some cases there are multiple elements under a single panel, as you can see in the image below.

i need to do the following correlation:
for the first element under panel 12: “PTF 128319” associate with “MU 129290”
for the second element under panel 12: “PTF 128320” associate AGAIN with “MU 129290”
… (in case there were more than 2 elemets)…
for the x element under panel 12: “PTF xxxxxx” associate AGAIN with “MU 129290”

the output list has to be a list like this, and have to be a correlation between the index of the element from the list elements (list 1) and its panel in the same index in the list panels (list 3)

|0 MU 129290|
|1 MU 129290|
|… |
|x MU 129290|

where at index 0 i have the panel of the element at same index (PTF 128319) in the list of elements
at index 1 i have the panel of the element at index 1 (PTF 128320) in the list of elements
and so on.

in addition of my example above continue with the following
let me know what you got

Thanks a lot for Your time, it works.

I have one last question, in the first image you posted, the “fire panels” on the top right corner of the picture. what is their category? fire alarm devices or electrical equipment? because i tried to set a fire alarm device as a “panel”, but i couldnt, i had to change category, into the electrical equipment.
Is it possible to set a fire alarm device as a panel without changing category into electrical equipment?

so happy that is worked :slight_smile:
for your question yes it’s electrical equipment, any distribution system needed to be a panel thats mean “electrical equipment”, this is how Revit work with fire alarm system.
in the family of electrical equipment there is electrical connector you decided to be power or fire or any system else