To stop a Jupyter notebook from within one of its Python cells, you can use one of the following methods:

1. Interrupt the Kernel

You can programmatically interrupt the kernel (i.e., stop the notebook execution) by running:

python
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import os
os._exit(00)

This will immediately terminate the Python process.

2. Raise a KeyboardInterrupt

You can simulate a keyboard interrupt (like pressing Ctrl+C in a terminal) with:

python
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raise KeyboardInterrupt

This will stop the current cell and return you to the notebook interface.

3. Use IPython Magic Commands

If you want to stop the notebook from a specific cell, you can use:

python
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%%javascript
IPython.notebook.kernel.execute('IPython.notebook.kernel.interrupt()');

This uses JavaScript to interrupt the kernel.

4. Restart the Kernel

If you want to restart the kernel (not just stop the current cell), you can use:

python
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from IPython.display import display, HTML
display(HTML("<script>Jupyter.notebook.kernel.restart()</script>"))

This will restart the kernel, stopping all execution.

Note: Methods 1 and 2 are more direct and will stop the notebook immediately, while methods 3 and 4 are more interactive and may require the notebook to be in a specific state. Use the method that best fits your needs!