Greetings. The iteration depends on what you are going to choose. If you select Points or Primitives, iteration respectively goes on each point or primitive and you not need to use loop explicitly unless you choose Detail in this case you have to use loop explicitly. For group simply you can specify it on group area of each wrangle node.
Yea I forgot you could specify the group directly on the wrangle node.
So basically I figured out what I wanted to do(see screenshot, write code to compute lenght of a curve).
My problem with this kind of stuff is that I came up with new “how can I do this” ideas when its midnight, and since I cant focus at that time I just asked here on the forum instead of focus on in the next day xD