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How to load/edit/run/save text files (.py) into an IPython notebook cell?

Posted by: admin November 1, 2017 Leave a comment

Questions:

I’ve recently moved over to using IPython notebooks as part of my workflow. However, I’ve not been successful in finding a way to import .py files into the individual cells of an open IPython notebook so that they can edited, run and then saved. Can this be done?

I’ve found this in the documentation which tells me how to import .py files as new notebooks but this falls short of what I want to achieve.

Any suggestions would be much appreciated,
thanks in advance.

Answers:

A text file can be loaded in a notebook cell with the magic command %load.

If you execute a cell containing:

%load filename.py

the content of filename.py will be loaded in the next cell. You can edit and execute it as usual.

To save the cell content back into a file add the cell-magic %%writefile filename.py at the beginning of the cell and run it. Beware that if a file with the same name already exists it will be silently overwritten.

To see the help for any magic command add a ?: like %load? or %%writefile?.

For general help on magic functions type “%magic”
For a list of the available magic functions, use %lsmagic. For a description
of any of them, type %magic_name?, e.g. ‘%cd?’.

See also: Magic functions from the official IPython docs.

EDIT: Starting from IPython 3 (now Jupyter project), the notebook has a text editor that can be used as a more convenient alternative to load/edit/save text files.

Questions:
Answers:

To write/save

%%writefile myfile.py

  • write/save cell contents into myfile.py (use -a to append). Another alias: %%file myfile.py

To run

%run myfile.py

  • run myfile.py and output results in the current cell

To load/import

%load myfile.py

  • load “import” myfile.py into the current cell

For more magic and help

%lsmagic

  • list all the other cool cell magic commands.

%COMMAND-NAME?

  • for help on how to use a certain command. i.e. %run?

Note

Beside the cell magic commands, IPython notebook (now Jupyter notebook) is so cool that it allows you to use any unix command right from the cell (this is also equivalent to using the %%bash cell magic command).

To run a unix command from the cell, just precede your command with ! mark. for example:

  • !python --version see your python version
  • !python myfile.py run myfile.py and output results in the current cell, just like %run (see the difference between !python and %run in the comments below).

Also, see this nbviewer for further explanation with examples.
Hope this helps.

Questions:
Answers:

Drag and drop a Python file in the Ipython notebooks “home” notebooks table, click upload. This will create a new notebook with only one cell containing your .py file content

Else copy/paste from your favorite editor 😉

Questions:
Answers:

I have found it satisfactory to use ls and cd within ipython notebook to find the file. Then type cat your_file_name into the cell, and you’ll get back the contents of the file, which you can then paste into the cell as code.