What I’m trying to do is to check to three lists.
List a= duct 1, duct2… duct n
List b= Room 1, Room 2…Room n
List c= (true, false. true)(true, true, false)…
So, for
Duct 1 check if list c is true , then get Room 1.
Duct 1 check if list c is true, then get Room 2.
Dusct 1 check if list c is true, then get Room n.
I did sth, but I can’t check for each room.
Thks for your time
I’ve solve one of my issues with this python:

Now the result of the python is:
I would like to group the result and just get:
[0]list: [0] H1-H2
[1]List: [0] H1-H3
[2]List: [H1
this could be done with a node that is in archi-lab package. It’s called “String from List” and works like this:
I am sorry about posting after you have figured this out, but it seems like it will be all for the best. 
You should be able to accomplish this with just the OOTB nodes: