graceful interrupt of while loop in ipython notebook - ipython

Question

I'm running some data analysis in ipython notebook. A separate machine collects some data and saves them to a server folder, and my notebook scans this server periodically for new files, and analyzes them.
I do this in a while loop that checks every second for new files. Currently I have set it up to terminate when some number of new files are analyzed. However, I want to instead terminate upon a keypress.
I have tried try-catching a keyboard interrupt, as suggested here: How to kill a while loop with a keystroke?
but it doesn't seem to work with ipython notebook (I am using Windows).
Using openCV's keywait does work for me, but I was wondering if there are alternative methods without having to import opencv.
I have also tried implementing a button widget that interrupts the loop, as such:
from ipywidgets import widgets
import time
%pylab inline
button = widgets.Button(description='Press to stop')
display(button)
class Mode():
def __init__(self):
self.value='running'
mode=Mode()
def on_button_clicked(b):
mode.value='stopped'
button.on_click(on_button_clicked)
while True:
time.sleep(1)
if mode.value=='stopped':
break
But I see that the loop basically ignores the button presses.

Answer 1

You can trigger a KeyboardInterrupt in a Notebook via the menu "Kernel --> Interrupt".
So use this:
try:
while True:
do_something()
except KeyboardInterrupt:
pass
as suggested here and click this menu entry.