openerp-expert-accounting team mailing list archive

[Ovnicraft <ovnicraft@xxxxxxxxx>]

On Sun, Nov 6, 2011 at 1:31 PM, Lorenzo Battistini <
lorenzo.battistini@xxxxxxxxxxx> wrote:

> 2011/11/6 Ovnicraft <ovnicraft@xxxxxxxxx>:
> >>
> >> >>> round(2.675, 2)
> >> 2.67
> >
> > The '2'  number is defined in currency.
>
> I perfectly know that. I was doing a python question. If you type
> 'round(2.675, 2)', python says '2.67', while it should be 2.68.
> Citing the page I was referring to:
>

You sure?

i get: 2.6800000000000002, please check my attach.

Regards,


>
> "The documentation for the built-in round() function says that it
> rounds to the nearest value, rounding ties away from zero. Since the
> decimal fraction 2.675 is exactly halfway between 2.67 and 2.68, you
> might expect the result here to be (a binary approximation to) 2.68.
> It’s not, because when the decimal string 2.675 is converted to a
> binary floating-point number, it’s again replaced with a binary
> approximation, whose exact value is
>
> 2.67499999999999982236431605997495353221893310546875
>
> Since this approximation is slightly closer to 2.67 than to 2.68, it’s
> rounded down.
>
> If you’re in a situation where you care which way your decimal
> halfway-cases are rounded, you should consider using the decimal
> module. Incidentally, the decimal module also provides a nice way to
> “see” the exact value that’s stored in any particular Python float"
>
>
> --
> Lorenzo Battistini
>



-- 
Cristian Salamea
@ovnicraft

Attachment: round.png
Description: PNG image