off topic but please forgive me me and answer
steve at REMOVE-THIS-cybersource.com.au
Fri Apr 2 04:44:40 CEST 2010
On Thu, 01 Apr 2010 19:49:43 -0500, Tim Chase wrote:
> David Robinow wrote:
>> $ python -c "print 1/2 * 1/2"
>> 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
> >>> 1/2 * 1/2.0
> Oh...wait ;-)
Tim, I'm sure you know the answer to this, but for the benefit of the
Original Poster, the problem is that you need to promote *both* divisions
to floating point. Otherwise one of them will give int 0, which gives 0.0
when multiplied by 0.5.
>>> 1.0/2 * 1/2.0
If you want an exact result when multiplying arbitrary fractions, you
need to avoid floats and decimals and use Fractions:
>>> Fraction(1, 2)**2
More information about the Python-list