IPyWalrus

IPyWalrus is a simple IPython (Jupyter) extension which enables you to use the walrus operator (PEP 572 - Assignment Expressions) := for usual assignments in IPython or Jupyter.

This part of the PEP:

There are a few places where assignment expressions are not allowed, in order to avoid ambiguities or user confusion:

Unparenthesized assignment expressions are prohibited at the top level of an expression statement. Example:

y := f(x)  # INVALID
(y := f(x))  # Valid, though not recommended

This rule is included to simplify the choice for the user between an assignment statement and an assignment expression -- there is no syntactic position where both are valid.

is completely valid but my IPython sessions of Jupyter notebooks are full of cells like this one:

and because it does not work in pure Python

I've prepared a small extension which makes it work:

Usage

Install the extension from pip or download the ipywalrus.py and put it somewhere in PYTHONPATH:

# pip install ipywalrus

and load it in IPython or Jupyter

%load_ext ipywalrus

If you want to enable this extension permamently, create a default profile (if you don't have one already) ipython profile create and then add ipywalrus to the list of extensions in ~/.ipython/profile_default/ipython_config.py.

License

MIT