Thx for that.
I didn't know the trick with Dictionary by grouping, very useful !
If I understand well, we can group by a parameter and then another, right ?
So in my case, I'd like to have [artist[album[title, title, title, title]][album[title, title, title]][album[title, title, title, title, title]][album[title]]] to have a tree.
So I need to do multiple Dictionary with maps in the for() or can I group directly in one dictionary ?
Thx.