[Python-Dev] Return type of round, floor, and ceil in 2.6

[Guido van Rossum]

On Jan 4, 2008 8:58 AM,  <skip at pobox.com> wrote:
>
>     Guido> Looks like in Python 2.6, round(0.5) right now returns 0.0,
>     Guido> whereas in 2.5, it returns 1.0.
>
>     Guido> I think it should return 1.0, for best compatibility with Python
>     Guido> 2.5.
>
> And for best compatibility with everything else! <0.5 wink>

Should I round that to 0 whole winks or 1 whole wink?

Rounding 0.5 to 0 is a new fad, called round-to-even, or
statistician's rounding. Read http://en.wikipedia.org/wiki/Rounding .
It's a standard, and more correct when doing statistical calculations.
That's why we've chosen it for Python 3.0. But it should not bleed
into Python 2.6.

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)