import a function from another .ipynb file

You’ll want to use the ipynb package/module importer. You’ll need to install it: pip install ipynb.

Create a Notebook named my_functions.ipynb. Add a simple function to it.

def factorial(n):
    if n == 0:
        return 1
    else:
        return n * factorial(n-1)

Then, create a second IPython Notebook and import this function with:

from ipynb.fs.full.my_functions import factorial

Then you can use it as if it was in the same IPython Notebook:

testing = factorial(5)

See the documentation for more details.