traversing sparse trees

Hi, I'm trying to find the indices of some successful intersections in a data tree so that I can use them to index into another array to do some brep splitting.

There is probably a much better grasshopperish way to do this, but I'm interested in the way to traverse datatrees in general.

The way I've been doing it so far is producing a list with a single entity in it rather than a list with nulls in it. The way my brain wants to think about this involves a sparse array that has a bunch of None/nulls in the places where there is no intersersection, and then a curve in the successful places.

The data tree is telling me which branch the successful projection is in, but not which leaf it is on.

This isn't particularly high priority, just curiosity. Here's an example: sparseTree.gh