From: Jeremy Hinegardner <jeremy@...>
Date: 2006-12-04T12:01:05+09:00
Subject: Re: number format


On Mon, Dec 04, 2006 at 10:48:41AM +0900, Li Chen wrote:
> Hi all,
> 
> I have a number, for example, 1.123456789. What is the Ruby way to
> change it into whatever number of floating points such as 1.12,
> 1.123,1.1234568 or 1.12345679.

You could use facets:

    % sudo gem install facets
    % irb

    irb(main):001:0> require 'rubygems'
    => true
    irb(main):002:0> require 'facet/float/round_at'
    => true
    irb(main):003:0> require 'facet/float/round_to'
    => true
    irb(main):004:0> x = 1.123456789
    => 1.123456789
    irb(main):005:0> x.round_at(3)
    => 1.123
    irb(main):006:0> x.round_at(7)
    => 1.1234568
    irb(main):007:0> x.round_at(100)
    => 1.123456789
    irb(main):008:0> x.round_to(0.001)
    => 1.123
    irb(main):009:0> x.round_to(0.000001)
    => 1.123457

enjoy,

-jeremy

-- 
========================================================================
 Jeremy Hinegardner                              jeremy@hinegardner.org