string formatting: engineering notation

Grant Edwards grante at visi.com
Wed Mar 14 22:10:41 CET 2007


On 2007-03-14, Steve Holden <steve at holdenweb.com> wrote:
> Darren Dale wrote:
>> Does anyone know if it is possible to represent a number as a string with
>> engineering notation (like scientific notation, but with 10 raised to
>> multiples of 3: 120e3, 12e-6, etc.). I know this is possible with the
>> decimal.Decimal class, but repeatedly instantiating Decimals is inefficient
>> for my application (matplotlib plotting library). If it is not currently
>> possible, do you think the python devs would be receptive to including
>> support for engineering notation in future releases?
>> 
> How close is this:
>
>  >>> "%.3e" % 3.14159
> '3.142e+00'

Not close at all. It should be "3.14159"

>>> "%.3e" % 31.4159
'3.142e+01'

should be 31.4159

>>> "%.3e" % 314.159
'3.142e+02'

should be 314.159

>>> "%.3e" % 31415.9
'3.142e+04'

should be 31.4159e3

-- 
Grant Edwards                   grante             Yow!  LOU GRANT froze
                                  at               my ASSETS!!
                               visi.com            



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