Group a list


Hello guys, do you know of a way where I can group elements using two different parameters ? I’m using this to sort my duct systems like a Revit Schedule.
The final result that I’m seeking is something like this :
Air Extraction :
200x300 : 5 meters



You could get the parameter of mechanical systems and use List.GroupByKey node. Below is an example of doors.


Hello @Kulkul, thank you for your answer I appreciate it but I published the question before I finished typing (Sorry about that, I’m new to the Forum) !

What I actually want dynamo to do is :
1-Group ducts by System type and then…
2- Group by Size.
3-Sum the lengths by Size.

For example :

400x200 : 12m
600x300 : 15m

300x500 6m


It seems like I can either Group by System Type or by Size but not both.

Here’s a snap of the humble result I got :


@MKK This should solve your issue. You need to use latest Dynamo 1.3 version. Currently your using older version.