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

Mark Dickinson dickinsm at gmail.com
Mon Mar 22 21:12:27 CET 2010

```On Mon, Mar 22, 2010 at 8:02 PM, Pierre B. <pierrebai at hotmail.com> wrote:
> Sorry to intervene out of the blue, but I find the suggested rule for
> fractional to decimal conversion not as clean as I'd expect.
>
> If fractions are converted to decimals when doing arithmetics, would it be
> worthwhile to at least provide a minimum of fractional conversion integrity?
> What I have in mind is the following rule:
>
> When doing conversion from fraction to decimal, always generate a whole number
> of repeating digits, always at least twice.
>
> Examples, with a precision of 5 in Decimal:
>
> 1/2 -> 0.50000
>
> 1/3 -> 0.33333
>
> 1/11 -> 0.090909
> # Note that we produced 6 digits, because
> # the repeating pattern contains 2 digits.
>
> 1/7 -> 0.142857142857
>  # Always at least two full patterns.

And for 1/123123127?  The decimal expansion of this fraction has a
period of over 15 million!

Sorry, but this doesn't seem like a feasible or desirable strategy.

Mark
```