How to run a Jupyter notebook .ipynb in python file .py?

You can convert the .ipynb file to a plain .py file using any of the methods mentioned here -

How do I convert a IPython Notebook into a Python file via commandline?

If, like me, you don't have access to the command line tools required - you can extract the source code from the .ipynb file as it is mostly a json file

import json
with open('somefile.ipynb') as f:
    nb_content = json.load(f)

for cell in nb_content['cells']:
    print(*cell['source'])

That should print out the whole source code to your terminal