From: Robert Dober <robert.dober@...>
Date: 2009-05-16T18:07:06+09:00
Subject: Re: Rounding any number (int or float) to 3 significant figures

On Fri, May 15, 2009 at 6:57 PM, Max Williams
<toastkid.williams@gmail.com> wrote:
> I have a requirement where i need to display (ie convert to a string)
> all digits to 3 significant figures.  (not the same as 3 decimal places)
>
> eg
>
>    23 => "23"
>    26759 => "26,800"
>    10.546 => "10.5"
>    3332332 => "3,330,000"
>    0.766 => "0.766"
>    0.00000766 => "0.00000766"
>
> Can anyone show me a neat way to do this?  I'd have thought that there'd
> be a method for it already but i can't find one.
>
> thanks!
> max
> --
> Posted via http://www.ruby-forum.com/.
>
>
At frirst sight and testing with the data you have given, the
following pretty much seems to do the trick:

  x.to_s.sub( /(\.0*\d{0,3}).*/, '\1' )

Did I overlook any edge cases?

HTH
R.