[Python-ideas] PEP 505: None-aware operators

[David Mertz]

On Thu, Jul 19, 2018, 5:12 AM Chris Angelico <rosuav at gmail.com> wrote:

> On Thu, Jul 19, 2018 at 4:06 PM, Greg Ewing <greg.ewing at canterbury.ac.nz>
> wrote:
> > There's a very long tradition of using the symbol "+" to
> > represent addition, so it's something most people are
> > familiar with. There's no such tradition for the new
> > operators being proposed.
>
> Okay. What about bitwise operators, then? They don't have centuries of
> mathematical backing to support them, yet it isn't considered
> "unpythonic" to have &|^~ peppering our code.
>

I have quite literally NEVER seem Python code with much use of the bitwise
operators. I guess the closest I've come is in some NumPy and Pandas code
where filters cannot use plain 'and' and ' or' but every student would find
it more intuitive if they could. E.g.

myDf[(myDf.field1 > 4) & (myDf.field2 < 2)]

Everyone still gets tripped up by the need for those parentheses because of
operator precedence. But this already yells or "special domain" rather than
"plain Python".

Indeed, it not uncommon or unreasonable to recommend using np.bitwise_and()
to avoid those confusing operators.

In the case where bitwise masking is used in its C manner, the code screams
special domain even more loudly. It definitely feels strongly unPythonic,
but it's often a reasonable compromise for dealing with just a little bit
of binary data without having to write a C extension.

I would ALWAYS want the code that used bitwise operators wrapped in a
separate function that most users and developers didn't need to look at,
but rather they'd call a more Pythonic API for the overall operation.

A huge difference is that bitwise operators do something you simply cannot
do other ways in Python at all. None-aware operators *at best* allow you to
write something with an existing straightforward approach using a couple
fewer lines. I think the result is ALWAYS less clear to read. Code golf is
an anti-goal in Python.

>
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