Replace <null> items in a list with a Zero value?

Hello again,

So I have a list of vectors that were created by using the "vector b/w 2 pts" component. Some values are null because there is no distance between the two points. In order to have the Vector list comply with an equal numbered list of Points, I need to replace the null items in the Vector list with a Zero value. Is this possible or is there another way around this? Thanks for the help

Ben

Replies to This Discussion

Permalink Reply by Danny Boyes on December 10, 2009 at 5:57am

Not sure if this is the most efficient way but it does achieve the desired effect.
1) Identify the Null Items [Logic>List>Null Item]
2) Create a SERIES numbering 0 to n, where n is the list length
3) Dispatch both lists equally using the boolean pattern from the Null Items
4) Generate the right number of ZEROs to replace the NULLs
5) MERGE each dispatched list together so that the ZEROs are tagged on the end (similar with the indices)
6) Sort the Indices List and Synchronously sort the original Merged list
7) Simplify tree (same as original structure)

A Similar approach can be taken to find a specific value and then replace eg find 0 and replace with 0.1

NB the graft tree component is redundant since I flattened the inputs to the Merge component.

Permalink Reply by Ben Compton on December 10, 2009 at 7:52am

Thanks a million. Worked great

Permalink Reply by Arthur Mamou-Mani on February 23, 2012 at 2:36am

Hi Danny,

Is there a way to do this with a branched list?

Struggling to adapt it or come up with a simple alternative...

Many thanks,

Arthur

Permalink Reply by Danny Boyes on February 23, 2012 at 2:51am

Hi Arthur,

This is how I would approach replacing Nulls now. The key change is that since 2009!!! the List Replace Component has come along.

Danny

Permalink Reply by Arthur Mamou-Mani on February 23, 2012 at 5:42am

Thanks a lot Danny, very helpful as always!

Hello from Tel Aviv :)

Permalink Reply by Arpan Bakshi on July 27, 2012 at 6:54am

Hi Danny, I am working through a similar problem, trying to replace all null values with 0 values. I am following the method you are showing, but it falls apart at sort list. Can you attach the definition file? Thank you!

Permalink Reply by Danny Boyes on July 27, 2012 at 12:04pm

Hi Arpan,

have a look at my reply to Arthur in February of this year (2012 for the benefit of future searches)

Permalink Reply by Arpan Bakshi on July 27, 2012 at 2:01pm

Couldn't find it ... do you have a title or link?

THX

Permalink Reply by Danny Boyes on July 27, 2012 at 3:54pm

Permalink Reply by John on July 27, 2012 at 4:32pm

OMG you have to do such convoluted crap just to what in C# would be: RemoveUnsucessfulFeatures().
Flawed. And crap.

Permalink Reply by Arpan Bakshi on July 27, 2012 at 4:38pm

John, from the look of RemoveUnsuccessfulFeatures(), it would remove all null items. But what would be the function for "Replace" UnsuccessfulFeatures with ___ value.

Permalink Reply by David Rutten on July 28, 2012 at 12:35pm

There is no such method in RhinoCommon or Grasshopper. Of course if someone goes through the trouble of writing it you can just call it. Similarly, if someone goes through the trouble of making a component for it (just did!) you can also just use that.

David Rutten

david@mcneel.com

Poprad, Slovakia