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print statement of ipywidgets not work in JupyterLab

See original GitHub issue

Phenomenon:

print statement not work in JupyterLab(can not see any output), but work in Jupyter Notebook

Environment:

Ubuntu 16.04
Chrome v66
JupyterLab 0.32.1
Python 3.6.5

Code:

from IPython.display import display
from ipywidgets import widgets
button = widgets.Button(description="Click Me!")
display(button)

def on_button_clicked(b):
    print("Button clicked.")

button.on_click(on_button_clicked)

Issue Analytics

State:
Created 5 years ago
Comments:8 (4 by maintainers)

Top GitHub Comments

12reactions

jasongroutcommented, May 17, 2018

You’ll need to use the output capturing mechanism in ipywidgets:

from IPython.display import display
from ipywidgets import widgets
button = widgets.Button(description="Click Me!")
display(button)

output = widgets.Output()

@output.capture()
def on_button_clicked(b):
    print("Button clicked.")

button.on_click(on_button_clicked)
display(output)

1reaction

jasongroutcommented, Mar 11, 2019

https://github.com/jupyterlab/jupyterlab/issues/3151#issuecomment-339476572 and https://github.com/jupyterlab/jupyterlab/issues/1254 give some more context on this.