to encompass a list or even a data tree structure, so if I feed the component with a list of numbers it will calculate the mass addition of each index as it updates.
I would like to know how to deal with this problem in terms of scripting. I know about ghpythonlib.treehelpers but I kindly ask you if you can provide me some example or tutorials in order to practice a little bit and figure out how to solve my problem.
I don’t know why you need it to be iterative or recursive, so perhaps I don’t understand your goal, but on the actual component (in GH, not in the code), just right click it and set x to List Access. Then in your code just do: a = sum(x).
By the way, pick a different name for the other variable, e.g. list_. list is a built-in and shouldn’t be used like this.
Your code will currently try to apply a class method from the type/class list to x, but either doesn’t have a list instance to apply it to or an item to append (e.g. l = [1,2,3]; list.append(l, 8) works, but that’s poor style compared to calling the instance’s own method).
Hi @James_Parrott and thank you for the reply.
Ok, I will pick a different name for the “list” variable.
About the first part of your answer, I probably didn’t explain well my goal.
I want to feed the component with a list of numbers like: [0,0,0,0] that in the following iteration could be like [1,1,1,1] and then like [1,0,0,1] , and I want the component to compute the sum like this: [2,1,1,2] WITHOUT storing informations inside the component (that’s why I used the “del” method").
Is it more clear now?
Thanks that’s perfectly clear now. It’s very straightforward, I just can’t think how to do it without storing information.
A list of sums depends on every element being summed (every summand) in the lists you give it. So at the very least you need to remember a partial sum, or store it as part of a component’s state.
You don’t have to use scriptcontext.sticky though, you can switch a GhPython component to SDK mode and store a list of partial sums in an instance variable on the component, like so for single numbers:
from numbers import Number
from ghpythonlib.componentbase import executingcomponent as component
class MyComponent(component):
a = 0
def RunScript(self, x, reset):
if reset is True:
self.a = 0
elif isinstance(x, Number):
self.a += x
return self.a
Otherwise if your lists of numbers always persist in Grasshopper, you can add a new List Access input for each list, and make RunScript accept *args
class MyComponent(component):
def RunScript(self, *args):
return [sum(elements) for elements in zip(*args)]
I tried with your suggestion but it’s not working.
At each iteration it adds to each number of the list a number corresponding to the lenght of the list itself.
So if I have:
[0,0,0,0] the next iteration will be [4,4,4,4] and so on…
