[Python-Dev] Mixing float and Decimal -- thread reboot

Mark Dickinson dickinsm at gmail.com
Mon Mar 22 21:45:39 CET 2010

On Mon, Mar 22, 2010 at 8:33 PM, Raymond Hettinger
<raymond.hettinger at gmail.com> wrote:
> While we're on the topic, I think you should consider allowing the Fraction()
> constructor to accept a decimal input.
> This corresponds to common schoolbook problems and simple client requests:
>   "Express 3.5 as a fraction".
>    >>> Fraction(Decimal('3.5'))
>   Fraction(7, 2)
> Unlike typical binary floats which use full precision, it is not uncommon
> to have decimal floats with only a few digits of precision where the
> expression as a fraction is both useful and unsurprising.

Sounds fine to me.  Fraction already accepts decimal floating-point
strings, so the implementation of this would be trivial (convert to
string, then call the Fraction constructor).


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