So I have spinning my wheels on this one for a couple days now:

## List A

Basically I have a list of coordinates, organized into a sublist based on their X and another sublist based on their Y value, leaving me with in essence a stack of points, with a variable Z position. These stacks are arrayed out across a large area both in the X and Y direction

## List B

I have another List of coordinates that I have manged to organize the same way as List A; only this list contains only one point. Note that the X and Y of each point corresponds to one ‘Stack’ or sublist found in List A.

What i’m trying to do is remove the entries of List A that have a Z value below the corresponding entry of List B. (By corresponding I mean the List B entry that matches the X and Y entries that defines the sublist ‘Stack’ of List A). Note that not every List A sublist ‘Stack’ contains 5 entries, and not all results would have only one value removed (it could be 0 it could be 5).

I apologize for not showing what I have tried; but thus far I haven’t even been able to get close. Typically I would write a series of 3 nested ‘For’ statements applied to List A. The first to find a matching X coordinate of the current Z Check Value. the second to find a matching Y. The last to process the Z Coordinates. Unfortunately I’m having a hard time making all the needed references to do this in python and pass the results back to Dynamo.