ipywidgets: Automatically update variable and run code after altering widget value - jupyter-notebook

Question

I have been trying to automatically update a variable and run a code snippet after altering a ipywidget.
So far the only partial solution I have found is to declare a global variable kind of following the example on the github (here):
import ipywidgets as widgets
from IPython.display import display
x = 5
slider = widgets.IntSlider()
slider.value = x
def on_change(v):
global x
x = v['new']
slider.observe(on_change, names='value')
display(slider)
Ideally what I am trying to achieve is to automatically change the x value after altering the widget without the use of global variables and also change some previously defined variables. It would be something like this:
x = 5
y = []
slider = widgets.IntSlider()
slider.value = x
def on_change(v):
x = v['new']
y.append(x)
slider.observe(on_change, names='value')
display(slider)

Answer 1

One way to achieve this would to be to make a class that accepts the new widget value, and does the derived calculation as well. I've done a simple addition but you could append to a list.
import ipywidgets as widgets
class Updated:
def __init__(self):
self.widget_value = None
self.derived_value = None
def update(self, val_dict) -> None:
self.widget_value = val_dict['new']
self.derived_value = self.widget_value + 10
update_class = Updated()
x = 5
y = []
slider = widgets.IntSlider()
slider.value = x
def on_change(v):
update_class.update(v)
slider.observe(on_change, names='value')
display(slider)
You can then see how update_class.widget_value and update_class.derived_value change as you move the slider.