Python Grasshopper list error

[Liu_Xiang (elena tt)]

I am trying to generate a rectangular within a grid created by GH. one way I was trying is use python to identify the index of the list then connect them.

but I was not quite understand the gh python,
Q1: input x is list of point, why it become a guiID in python?
Q2:I trying to add text dot to the python, but it does not show up

GH file here
Q_python in GH.gh (9.4 KB)

[Adam_M (Adam Mounsey)]

Here is one way with python, plus a native gh option.
Q_python in GH_v2.gh (13.9 KB)

[Liu_Xiang (elena tt)]

thanks so much adam, I learn a lot just see your python.

[Liu_Xiang (elena tt)]

it’s so weird, when I just run the first part of your python, there is an error, “GUID” object has no atribute ‘branchcount’, do you know what’s wrong?

[kev.r (Kevin)]

@Liu_Xiang

there is an error, “GUID” object has no atribute ‘branchcount’, do you know what’s wrong?

Right-click on the x input and select Tree Access

-Kevin

[Liu_Xiang (elena tt)]

@Adam_M

Here is one way with python, plus a native gh option.

I also tried to identify the list with your python, not get it right, it does not read the branch? and it clappse all at end row.

Q_ how to identify the list pythonGh.gh (7.5 KB)

[kev.r (Kevin)]

Changed code at lines 11 and 13.

Flattened Location input to Text Tag 3D component.

Q_ how to identify the list pythonGh_re.gh (10.2 KB)

-Kevin

[Liu_Xiang (elena tt)]

Thanks , I should read the imput data structure.
Also curious, why the th.tree_to_list return , give this “ironpython.runtime.list”, but in python the line 8 give GUID of the points

[kev.r (Kevin)]

@Liu_Xiang

curious, why the th.tree_to_list return , give this “ironpython.runtime.list”, but in python the line 8 give GUID of the points

After using the method plist = th.tree_to_list(pt) the the plist variable references a list of lists (nested list). This isn’t a native type for grasshopper so if you want to use it for further processing in grasshopper you’ll need to convert it back to a DataTree with the method plist = th.list_to_tree(plist) at the end of your code.

-Kevin

[Liu_Xiang (elena tt)]

just to dig a little further. " A Data Tree is a hierarchical structure for storing data in nested lists." but seems as you explained, data tree in grasshopper is different than the nested list in python. could you help me understand the data tree in grasshopper more?

[AndersDeleuran]

Have a look here:

Grasshopper data trees and Python

And here:

Tree operations in Python

There’s also the documentation of the DataTree class itself: https://developer.rhino3d.com/wip/api/grasshopper/html/T_Grasshopper_DataTree_1.htm And some minimal examples for reading and writing two dimensional trees: Read: """ Read the Grasshopper Datatree "FooTree" and translates it to a nested Python list """ pyList = [list(b) for b in FooTree.Branches] Write: import Grasshopper as gh def listToTree(nestedList): """ Convert a nested python iterable to a datatree """ …