[Python-ideas] real numbers with SI scale factors

[Nikolaus Rath]

On Aug 29 2016, Ken Kundert <python-ideas-jl/PDlM0qtzz1n+OaKNE4w at public.gmane.org> wrote:
> Nikolaus,
>     I have belatedly realized that this kind of hyperbole is counter productive.
> So let me back away from that statement and instead try to understand your
> reasons for not liking the proposal.
>
> Do you think there is no value to be able to naturally read and write numbers
> with SI scale factors from Python? Or is your issue with something about my
> proposal?

* I think there is no value gained by being able to write 32.3m instead
  of 32.3e6. I think the second one is clear to everyone who uses SI
  prefixes, while the first one just introduces a lot of
  complexities. Most of them have been mentioned already:

  - no deducible ordering if one doesn't know the prefixes
  - potential for ambiguity with Exa
  - question about base 2 vs base 10, e.g what do you expect to be
    stored in *size* if you reed this:
    "size = 10M # we need that many bytes" 
  - rather abitrary naming ("M" and "m" vs "T" and "p").

* I think having SI *Unit* support "32.3 kN" would be nice, but only if
  there is a space between number and unit, and only if the unit
  actually get's attached to the number. But your proposal would 
  result in 1km + 1µN == 2 being true.


Best,
-Nikolaus

-- 
GPG encrypted emails preferred. Key id: 0xD113FCAC3C4E599F
Fingerprint: ED31 791B 2C5C 1613 AF38 8B8A D113 FCAC 3C4E 599F

             »Time flies like an arrow, fruit flies like a Banana.«