Pulling ipywidget value manually

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I have this code ipython code:

import ipywidgets as widgets
from IPython.display import display
import time

w = widgets.Dropdown(
    options=['Addition', 'Multiplication', 'Subtraction'],
    value='Addition',
    description='Task:',
)

def on_change(change):
    print("changed to %s" % change['new'])

w.observe(on_change)

display(w)

It works as expected. When the value of the widget changes, the on_change function gets triggered. However, I want to run a long computation and periodically check for updates to the widget. For example:

for i in range(100):
    time.sleep(1)
    # pull for changes to w here.
    # if w.has_changed:
    #     print(w.value)

How can I achieve this?

For reference, I seem to be able to do the desired polling with

import IPython
ipython = IPython.get_ipython()
ipython.kernel.do_one_iteration()

(I'd still love to have some feedback on whether this works by accident or design.)

Simple Widget Introduction — Jupyter Widgets 7.5.1 , Try dragging the slider below and watch the slider above. Instead of attempting to manually synchronize the values of the two widgets, you can use the link or� Linking two similar widgets¶. If you need to display the same value two different ways, you’ll have to use two different widgets. Instead of attempting to manually synchronize the values of the two widgets, you can use the link or jslink function to link two properties together (the difference between these is discussed in Widget Events).

I think you need to use threads and hook into the ZMQ event loop. This gist illustrates an example:

https://gist.github.com/maartenbreddels/3378e8257bf0ee18cfcbdacce6e6a77e

Also see https://github.com/jupyter-widgets/ipywidgets/issues/642.

Pulling ipywidget value manually - ipython - html, Pulling ipywidget value manually - ipython. When the value of the widget changes, the on_change function gets triggered. However, I want to run a long� The following are 34 code examples for showing how to use ipywidgets.Text().These examples are extracted from open source projects. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example.

To elaborate on the OP's self answer, this does work. It forces the widgets to sync with the kernel at an arbitrary point in the loop. This can be done right before the accessing the widget.value.

So the full solution would be:

import IPython
ipython = IPython.get_ipython()

last_val = 0
for i in range(100):
    time.sleep(1)
    ipython.kernel.do_one_iteration()
    new_val = w.value
    if new_val != old_val:
        print(new_val)
        old_val = new_val

[PDF] ipywidgets Documentation, Notice that the output is updated even while dragging the mouse on the to manually synchronize the values of the two widgets, you can use� The following are 34 code examples for showing how to use ipywidgets.Dropdown().These examples are extracted from open source projects. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example.

A slight improvement to the ipython.kernel.do_one_iteration call used

# Max iteration limit, in case I don't know what I'm doing here...
for _ in range(100):
  ipython.kernel.do_one_iteration()
  if ipython.kernel.msg_queue.empty():
    break

In my case, I had a number of UI elements, that could be clicked multiple times between do_one_iteration calls, which will process them one at a time, and with a 1 second time delay, that could get annoying. This will process at most 100 at a time. Tested it by mashing a button multiple times, and now they all get processes as soon as the sleep(1) ends.

Updating dropdown.options does not update value or label � Issue , jasongrout commented on Feb 5, 2018. I reproduced this with: from ipywidgets import *� Basically use ipywidget widget manager to do everything. We create the manager, and give it the command chanel; Manager will render the widgets. We can give the manager a map of request id to html elements. Will allow us to render the ipywidget in the right spot.

Linking widgets for strings � Issue #2092 � jupyter-widgets/ipywidgets , list of identifiers with first item (and defualt widget value) 'FREE'. that whenever an identifier is entried manually in the text field, the value of� If the keyword argument is a Widget instance with a value attribute, that widget is used. Any widget with a value attribute can be used, even custom ones. Otherwise, the value is treated as a widget abbreviation that is converted to a widget before it is used. The following table gives an overview of different widget abbreviations:

python-jupyter_ipywidgets-7.2.1-bp150.2.4, ([#1923](https://github.com/jupyter-widgets/ipywidgets/pull/1923)) * A new option The `Play` widget range is now inclusive (max value is max, instead of max-1), to be Fix version in py file * Run interact manual on Text widget submit * Fix� Linking two similar widgets¶. If you need to display the same value two different ways, you’ll have to use two different widgets. Instead of attempting to manually synchronize the values of the two widgets, you can use the link or jslink function to link two properties together (the difference between these is discussed in Widget Events).

3.3. Mastering widgets in the Jupyter Notebook, import ipywidgets as widgets from ipywidgets import HBox, VBox import numpy By default, the @interact decorator displays a slider to control the value passed to the function: decorator which provides a button to call the function manually. For both integer and float-valued sliders, you can pick the initial value of the widget by passing a default keyword argument to the underlying Python function. Here we set the initial value of a float slider to 5.5 .

Comments
  • This is exactly what I've been looking for, although for me it was a button on_click
  • Thanks for pointing me in the right direction. I'll try that out!