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

Steven D'Aprano steve at pearwood.info
Sat Feb 13 09:58:52 EST 2016

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

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