Restart ipython Kernel with a command from a cell

Question

Is it possible to restart an ipython Kernel NOT by selecting Kernel > Restart from the notebook GUI, but from executing a command in a notebook cell?

Not intentionally, but any command which kills the kernel process will cause it to be automatically restarted. I think IPython catches `sys.exit()`, but [os._exit()](https://docs.python.org/3/library/os.html#os._exit) will make it die. This skips all of Python's normal cleanup (e.g. `atexit`), though. If you just want a way to restart the kernel from the keyboard, the shortcut is `00`. — Thomas K, Jun 13 '16 at 10:35
Thank you very much. Now that is definitely something I will have to check. Thank you! — pebox11, Jun 13 '16 at 11:43

score 39 · Accepted Answer · answered Jun 23 '16 at 13:58

39

As Thomas K. suggested, here is the way to restart the ipython kernel from your keyboard:

import os
os._exit(00)

answered Jun 23 '16 at 13:58

pebox11

3,377
5
32
57

9

Another possibility is to call the kernel.restart() method directly, as described in https://stackoverflow.com/a/47055462/104707 – amain Jan 26 '18 at 15:42
5

This will exit ipython in my case, not restarting it. – azzamsa Aug 16 '19 at 07:31
6

@azzamsa it exits and automatically restarts the kernel. The problem, in my case, is that I still have to click on a pop up message to restart the kernel. – aerijman Dec 04 '19 at 00:50
1

It just exits ipython for me. – Simd Mar 24 '22 at 17:30
It doesn't work when I use IPython in Mac's terminal. – Tony Mai Jun 29 '22 at 08:50
it doesn't save you the "ok" press on the pop-up window. – NoamG Aug 28 '22 at 15:49
why `00` and not just `0`? – blambert Mar 02 '23 at 19:01

score 15 · Answer 2 · edited Jul 05 '20 at 19:07

15

import IPython

IPython.Application.instance().kernel.do_shutdown(True) #automatically restarts kernel

edited Jul 05 '20 at 19:07

Jeremy Caney

7,102
69
48
77

answered Jul 05 '20 at 18:21

user1348692

177
1
5

In ipython 8.1.1. this gives ----> 1 IPython.Application.instance().kernel.do_shutdown(True) AttributeError: 'TerminalIPythonApp' object has no attribute 'kernel' – Simd Mar 24 '22 at 17:28
1

In IPython 8 and above, kernel can be accessed via `get_ipython().kernel`, so the above becomes `get_ipython().kernel.do_shutdown()` —`get_ipython` is a global available in Jupyter notebook and Colab but not interactive python shell. – Matteo Ferla May 24 '22 at 11:07

score 7 · Answer 3 · answered Aug 22 '18 at 22:15

7

To define a function that restarts the Jupyter kernel, I've successfully used:

from IPython.display import display_html
def restartkernel() :
    display_html("<script>Jupyter.notebook.kernel.restart()</script>",raw=True)

then calling

restartkernel()

when time for the restart.

answered Aug 22 '18 at 22:15

wpressNR

87
1
1

4

It does not restart the kernel. – aerijman Dec 04 '19 at 00:48

score 5 · Answer 4 · answered Nov 14 '22 at 17:06

5

If you are using jupyter, there's also this option:

%reset -f

This is not going to fully restart, just reset all variables, which is sometimes what we want.

answered Nov 14 '22 at 17:06

Fernando Wittmann

1,991
20
16

score 0 · Answer 5 · edited Dec 03 '21 at 11:41

0

Try print(chr(12)).

I am not sure what this function does behind the scenes, but if you are looking for a way to hide all previous outputs (such as in-memory 'card' game), it works.

edited Dec 03 '21 at 11:41

Roman Sinyakov

559
1
6
24

answered Nov 30 '21 at 17:10

user17554465

1

`print(chr(12))` just prints a control character called "form feed", which is unicode 0x000C (12). It doesn't do anything else. – Noah Wiggin Jul 02 '23 at 05:24

Restart ipython Kernel with a command from a cell

5 Answers5

Linked