1.090516455488E9 / 1000000.000 ???

[Felipe Almeida Lessa]

Em Ter, 2006-03-28 às 16:59 +0200, Fredrik Lundh escreveu:
> and consider using
> 
>     http://www.python.org/doc/lib/module-decimal.html
> 
> instead.

$ python2.4
Python 2.4.2 (#2, Nov 20 2005, 17:04:48)
[GCC 4.0.3 20051111 (prerelease) (Debian 4.0.2-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from decimal import Decimal
>>> a = Decimal("1.090516455488E15")
>>> a
Decimal("1.090516455488E+15")
>>> b = a / 1000000
>>> b
Decimal("1090516455.488")
>>> str(b)
'1090516455.488'

*But*,

$ python2.4 -mtimeit -s 'from decimal import Decimal; a =
Decimal("1.090516455488E15")' 'a/1000000'
1000 loops, best of 3: 222 usec per loop
$ python2.4 -mtimeit -s 'a=1.090516455488E15' 'a/1000000' 1000000 loops,
best of 3: 0.234 usec per loop
$ calc 222/0.234
        ~948.71794871794871794872

Decimal is almost one thousand times slower. Do you really need this
accuracy?

HTH,

-- 
Felipe.