[SciPy-user] nice floating point display ?

[Robert Kern]

On Thu, Feb 28, 2008 at 5:43 PM, Stef Mientki <s.mientki at ru.nl> wrote:
> hello,
>
>  I'm creating an float / log slider,
>  now I need a nice representation of the min / max / value
>  of the slider.
>
>  For some unknown reason
>   set_printoptions(precision=2)
>  doesn't work,
>  and I doubt if it is adequate in my application,
>  because precision and notation depends more on the range
>  than on the actual value itself.
>
>  Does anyone has a elegant solution ?

set_printoptions() doesn't affect Python floats at all, and that looks
like what you are trying to print.

You can explicitly format the numbers yourself:

http://docs.python.org/dev/library/stdtypes.html#string-formatting-operations


In [39]: x = 1.2345678901

In [40]: '%f' % x
Out[40]: '1.234568'

In [41]: '%g' % x
Out[41]: '1.23457'

In [42]: '%1.2f' % x
Out[42]: '1.23'

In [43]: '%1.10f' % x
Out[43]: '1.2345678901'

In [46]: '%f' % (x*1e20)
Out[46]: '123456789009999986688.000000'

In [47]: '%g' % (x*1e20)
Out[47]: '1.23457e+20'

In [48]: '%e' % x
Out[48]: '1.234568e+00'

In [56]: '%.*f' % (3, x)
Out[56]: '1.235'

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
  -- Umberto Eco