Filter and recombine on nested lists

Lists-Logic
1

Hello everyone,

I have an issue regarding the filter node in Dynamo, which does not keep the original order of elements after filtering.

I really need this because I want to filter a nested list of points with the purpose to modify only some of them and after that I want to recombine the list with the not-modified points, in order to redraw the new-form modified line.
Right now, the ListFilterByBoolMask Node is filtering without keeping the elements position and then when I rejoin the with ListJoin node, it makes two separate nested lists: one for the “IN” output and one for the “OUT” output.

In fact, in Grasshopper, there is a component who does exactly this(Dispatch), keeping the filtered elements in place as empty list. It is possible to do this in Dynamo?

Best regards,
Alex

2

If you don’t mind working with something other than empty lists (null in example below) than this may be a viable approach:

image.jpg597Ă—550 129 KB

3

Or similar syntax in DesignScript:

image.jpg807Ă—525 135 KB

1 Like
4

Replace By Condition:

5

Yes, nice solution, but the problem is that I need two outputs, one for the IN list with the null list, and the other for OUT, also with the null list mixed in.

6

Can you share a little more of your graph so we can see your intent? Maybe we can find another way of structuring the graph?

7

Yeah, sure! This is a bigger picture of the definitions.

In fact, the final goal is to reunify all the points seen in the background for each curve, this is why I need to keep the list order.