How to output results for group by key?

Hi Greetings.

I would like to seek on group by key. How do you output the results to excel for group by key?

Perhaps with this:

Really need to see more of what you have done and an explanation of what you are after to provide meaningful input though.

Hi Jacob,

Apologies for my unclear explanation. I would like to make myself clearer. As you can see in Picture 1, this is the output result which I have generated. I would like to improve the results by grouping the grilles of the same flow rate and same designation together as shown in Picture 2.

Picture 1:

Picture 2:

This is part of my dynamo script. How would you help to enhance it to produce the results in picture 2?

List.GroupByKey to group all of your items by one value. Repeat as desired, and watch your list levels and lacing.
List.FirstItem to get a sublist from the sublists as you only want to write this once. Keep mindful of your list levels and lacing.
List.Count to count the number of instances in each sublist. Be sure to watch those list levels and lacing.
List.InsertItemAtIndex to add the count at the desired index. Not sure I mentioned it yet but list levels and lacing will matter here.