Hello !
I am trying to manipulate some data. What I want to achieve is to get a parameter from a Generic Model which is inside a Group and take that Parameter Value of that Generic Model. Once I have it I want to place that Value as a string in a new parameter which is the Group’s. However in order to achieve that I want to filter the groups from this list and I can’t get it to work. Any ideas would be much appreciated ! 
I think List.GroupByKey is what you are looking for.
PS
Showing more of your graph or posting your .dyn makes it easier for people to help you.
Here is my nodes. From some reason I can’t get List.Remove.IfNot to work.
Normally it should filter Groups.
Hi @d.tashev ,
There are multiple ways to filter you elements.
You can group as @bvs1982 says.
This is an other way to filter the elements and delete the groups:
Aaaand another option (in case you want to use the List.RemoveIfNot node 
).
@bvs1982 @jw.vanasselt
Nice one guys,
been a massive help, really.
Need to dig more into the Revit API and Dynamo in general
