From: Bil Kleb <Bil.Kleb@...>
Date: 2009-08-05T20:30:06+09:00
Subject: Re: zero placeholder exponential sprintf?

Harry Kakueki wrote:
> On Wed, Aug 5, 2009 at 7:00 AM, Bil Kleb<Bil.Kleb@nasa.gov> wrote:
>> We have a request for 0.112345e+03 instead of,
>>
>>  % ruby -e "puts '%.6e' % [ 1.123450e+2 ]"
>>  1.123450e+02

> I may be missing what you are after, but....
> Does it need to be sprintf?

Sorry for the confusion, String::% uses Kernel::sprintf -- see

   http://www.ruby-doc.org/core/classes/String.html#M000770

So, to match my subject line better and correct the desired
formatted number:

  ruby -e "puts sprintf('%.6e',1.123450e+2)" #=> 1.123450e+02

but I want '0.112345e+03', i.e., a leading zero placeholder.

@drbrain says this probably violates IEEE,

  http://twitter.com/drbrain/statuses/3132296591
  http://twitter.com/drbrain/statuses/3132322954

> require 'bigdecimal'
> p BigDecimal.new(1.12345e+2.to_s).to_s  #=> "0.112345E3"

Hmmm, now just need the '+0' part in the exponent and control
of the number of decimal places?

Regards,
--
Bil Kleb
http://fun3d.larc.nasa.gov