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Hi,

while I usually cope with the woes of floating point issues, this is
one, that I didn't expect:

>>> round(2.385, 2)
2.3799999999999999

Doesn't the docs say, it's rounded up for this case?

<quote>
Values are rounded to the closest multiple of 10 to the power minus n;
if two multiples are equally close, rounding is done away from 0
</quote>

Well, that one is clearly rounding down.

What's up, eh, down here?

Pete

Python 2.6 (r26:66714, Feb 8 2011, 08:50:11)
[GCC 4.3.2 [gcc-4_3-branch revision 141291]] on linux2

Hans-Peter Jansen wrote:

> Hi,
>
> while I usually cope with the woes of floating point issues, this is
> one, that I didn't expect:
>
>>>> round(2.385, 2)
> 2.3799999999999999
>
> Doesn't the docs say, it's rounded up for this case?
>
> <quote>
> Values are rounded to the closest multiple of 10 to the power minus n;
> if two multiples are equally close, rounding is done away from 0
> </quote>
>
> Well, that one is clearly rounding down.
>
> What's up, eh, down here?

2.385 isn't really 2.385:

Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56)
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> repr (2.385)
'2.3849999999999998'
>>>

so it correctly rounded down. You need to use Decimal numbers if you want
numbers that behave the way they look.

Mel.