Variable List Merge / "Overwrite" Positioned List Values From Another List

Replies to This Discussion

Permalink Reply by Andrew Heumann on July 3, 2010 at 9:31pm

here's how I would do it:
1. graft all of the lists
2. merge them together (you will get a data tree containing n lists with 3 items each
3. create a new list with n integers, where the value is the index of the list you want to draw from for that index number.
4. graft the new list of integers
5. use the list item component, with the merged grafted lists into L, and the new list of integers into i.
6. flatten the resulting list.

Example:

list A: list B: list C:
100 200 300
101 201 301
102 202 302
103 203 303
104 204 304

Integer List:
0
0
2
1
2

list item component returns:
100
101
302
203
304

I hope this is clear enough - and close enough to what you were trying to do.

Andrew

Permalink Reply by Max D on July 4, 2010 at 5:40am

wow, that is very smart!! thank you so much! Never thought about using the tree structure to store alternate values in that way. I'd probably input the integer list(s) through a panel as if writing a "weave sheet" of sorts.

Have a lovely Sunday,

M

Permalink Reply by Danny Boyes on July 4, 2010 at 2:57pm

If you use the latest version of GH v0.7.00030 there is a list insert component and used in conjunction with the cull index component this would achieve what you want.

Permalink Reply by taz on July 5, 2010 at 10:12am

I think using branch names as an index would be the best way to go since if the branch names are formatted similarly merging will automatically combine them in the correct order.

Using the new insert list component would be slightly more work since after values are removed from a list the list length changes and so do the index values to reinsert the modified data.

Permalink Reply by Danny Boyes on July 5, 2010 at 10:19am

Permalink Reply by taz on July 5, 2010 at 10:25am

But say the values you remove aren't consecutive, like if you remove 2, 5 and 7 and want to replace them with values in their original list location...

Permalink Reply by Danny Boyes on July 5, 2010 at 10:28am

Permalink Reply by Marc Syp on July 5, 2010 at 10:53am

I always thought that the Stream Filter and Stream Gate components should accept multiple gate indices... anyway, so I wrote a really simple VB script about 6 months ago to accomplish the task. Given up to 4 lists of identical length, you provide a list of indices to tell the component which list to pull from for each index position. I use this extensively for mixing influence systems on a complex construction.

Attachments:

• SYP-Useful-MixLists.ghx, 114 KB

Permalink Reply by David Lister on June 5, 2011 at 7:37pm

Is there a way to simply amend this script so that the filter indice denotes which LIST to return, and it's output from 'S' is a branch?

 

ie. with the panels used above would return

{0;0}

0 | 0

1 | 0

2 | 0

3 | 0

4 | 0

5 | 0

 

{0;1}

0 | A

1 | B

2 | C

3 | D

4 | E

5 | F

 

{0;1}

0 | 1

1 | 2

2 | 3

3 | 4

4 | 5

5 | 6

 

and so on...

Permalink Reply by Ralph Spencer Steenblik on April 4, 2018 at 10:34am

Still helpful, thank you very much!

Permalink Reply by Wess on November 5, 2011 at 6:09am

Hello Danny,

I'm making a script where I use the List Insert component also. But it isn't working the way I want.

I made an exact copy of your List Insert script from above, but my result is different.
Grasshopper is using the two lists alternately. See my image.

Do you know why? I'm using grasshopper version 0.8.0051

Thanks in advance,

 

Wessel

Permalink Reply by Max D on July 5, 2010 at 10:58am

this is all incredibly insightful, thank you! I'm glad there are so many variant methods.