[Python-Dev] PEP 515: Underscores in Numeric Literals (revision 3)

[Steven D'Aprano]

On Sat, Feb 13, 2016 at 09:48:49AM +0100, Georg Brandl wrote:
> Hi all,
> 
> after talking to Guido and Serhiy we present the next revision
> of this PEP.  It is a compromise that we are all happy with,
> and a relatively restricted rule that makes additions to PEP 8
> basically unnecessary.
> 
> I think the discussion has shown that supporting underscores in
> the from-string constructors is valuable, therefore this is now
> added to the specification section.

What about Fraction? Currently this is legal:

py> Fraction("1/1000000")
Fraction(1, 1000000)


I think the PEP should also support underscores in Fractions:

Fraction("1/1_000_000")


> The remaining open question is about the reverse direction: do
> we want a string formatting modifier that adds underscores as
> thousands separators?

Yes please.


> Open Proposals
> ==============
> 
> It has been proposed [11]_ to extend the number-to-string formatting
> language to allow ``_`` as a thousans separator, where currently only
> ``,`` is supported.  This could be used to easily generate code with
> more readable literals.

/s/thousans/thousands/



-- 
Steve