From: Kirk Haines <wyhaines@...>
Date: 2010-08-31T04:13:48+09:00
Subject: Re: Time#round in 1.9

On Mon, Aug 30, 2010 at 12:42 PM, Intransition <transfire@gmail.com> wrote:
> Anyone know about Time#round in 1.9. Apparently it exists but it seems
> to do nothing but eat up cpu cycles.
>
>  ruby-1.9.2-p0 > t = Time.new
>   => 2010-08-30 14:34:03 -0400
>  ruby-1.9.2-p0 > t.round(100000)
>   => 2010-08-30 14:34:03 -0400
>  ruby-1.9.2-p0 > t.round(1000000)
>   => 2010-08-30 14:34:03 -0400

A voice was heard to utter: "Use the source, Luke! Errr, uh, Trans.
Oh, and the docs!"

/*
 * call-seq:
 *   time.round([ndigits])   -> new_time
 *
 * Rounds sub seconds to a given precision in decimal digits (0 digits
by default).
 * It returns a new time object.
 * _ndigits_ should be zero or positive integer.
 *
 *     require 'time'
 *
 *     t = Time.utc(2010,3,30, 5,43,"25.123456789".to_r)
 *     p t.iso8601(10)           #=> "2010-03-30T05:43:25.1234567890Z"
 *     p t.round.iso8601(10)     #=> "2010-03-30T05:43:25.0000000000Z"
 *     p t.round(0).iso8601(10)  #=> "2010-03-30T05:43:25.0000000000Z"
 *     p t.round(1).iso8601(10)  #=> "2010-03-30T05:43:25.1000000000Z"
 *     p t.round(2).iso8601(10)  #=> "2010-03-30T05:43:25.1200000000Z"
 *     p t.round(3).iso8601(10)  #=> "2010-03-30T05:43:25.1230000000Z"
 *     p t.round(4).iso8601(10)  #=> "2010-03-30T05:43:25.1235000000Z"
 *     p t.round(5).iso8601(10)  #=> "2010-03-30T05:43:25.1234600000Z"
 *     p t.round(6).iso8601(10)  #=> "2010-03-30T05:43:25.1234570000Z"
 *     p t.round(7).iso8601(10)  #=> "2010-03-30T05:43:25.1234568000Z"
 *     p t.round(8).iso8601(10)  #=> "2010-03-30T05:43:25.1234567900Z"
 *     p t.round(9).iso8601(10)  #=> "2010-03-30T05:43:25.1234567890Z"
 *     p t.round(10).iso8601(10) #=> "2010-03-30T05:43:25.1234567890Z"
 *
 *     t = Time.utc(1999,12,31, 23,59,59)
 *     p((t + 0.4).round.iso8601(3))    #=> "1999-12-31T23:59:59.000Z"
 *     p((t + 0.49).round.iso8601(3))   #=> "1999-12-31T23:59:59.000Z"
 *     p((t + 0.5).round.iso8601(3))    #=> "2000-01-01T00:00:00.000Z"
 *     p((t + 1.4).round.iso8601(3))    #=> "2000-01-01T00:00:00.000Z"
 *     p((t + 1.49).round.iso8601(3))   #=> "2000-01-01T00:00:00.000Z"
 *     p((t + 1.5).round.iso8601(3))    #=> "2000-01-01T00:00:01.000Z"
 *
 *     t = Time.utc(1999,12,31, 23,59,59)
 *     p (t + 0.123456789).round(4).iso8601(6)  #=>
"1999-12-31T23:59:59.123500Z"
 */

Below that is a short, simple to follow implementation.  You are
telling it to round to 100000 or 1000000 digits. That's probably not
what you mean?


Kirk Haines