[Python-ideas] [RFC] draft PEP: Dedicated infix operators for matrix multiplication and matrix power

[Joseph Martinot-Lagarde]

Robert Kern <robert.kern at ...> writes:

> 
> On 2014-03-14 13:20, M.-A. Lemburg wrote:
> > On 14.03.2014 12:25, Robert Kern wrote:
> >> On 2014-03-14 10:16, M.-A. Lemburg wrote:
> >>
> >>> I have some questions:
> >>>
> >>> 1. Since in math, the operator is usually spelt "·" (the center dot,
> >>>      or "." but that's already reserved for methods and attributes in
> >>>      Python), why not try to use that instead of " <at> " (which in Python
> >>>      already identifies decorators) ?
> >>
> >> I think the current feeling of the Python core team is against
including non-ASCII characters in the
> >> language's keywords or operators. Even if that were not so, I would
still recommend against it
> >> because it would be quite difficult to type. I don't know off-hand the
key combination to do it on
> >> my native system, and it would change from system to system.
> >
> > That's a fair argument. How about using the degree symbol instead: "°" ?
> >
> > (A ° B).T == B.T ° A.T
> 
> Your point is taken, though. I do find these smaller symbols more readable
and 
> similar to standard mathematical notation than an  <at>  sign, which is as
big or 
> bigger than most uppercase characters. Unfortunately, ASCII leaves us few 
> single-character options.
> 

Putting aside tha ascii problem, ° is easily written using a AZERTY
keyboard. It is smaller and less convoluted than @ and looks like the
mathematical notation for function composition, which is similar to matrix
multiplication.
Still, not ascii and not displayed on every keyboard...