off topic but please forgive me me and answer

Lie Ryan lie.1296 at gmail.com
Fri Apr 2 04:50:39 CEST 2010


On 04/02/10 13:01, Patrick Maupin wrote:
> On Apr 1, 7:49 pm, Tim Chase <python.l... at tim.thechases.com> wrote:
>> David Robinow wrote:
>>> $ python -c "print 1/2 * 1/2"
>>> 0
>>
>>>  But that's not what I learned in grade school.
>>> (Maybe I should upgrade to 3.1?)
>>
>> That's because you need to promote one of them to a float so you
>> get a floating-point result:
>>
>>    >>> 1/2 * 1/2
>>    0
>>    >>> 1/2 * 1/2.0
>>    0.0
>>
>> Oh...wait ;-)
>>
>> -tkc
> 
> Hmmm, I think I'm starting to see why we need math.fsum() to take care
> of those rounding errors...

hmm?

>>> import math
>>> math.fsum([1/2, 1/2])
0.0

it doesn't appear to take care of those rounding errors, not in this
case at least.



More information about the Python-list mailing list