John Carter a ñÄrit :
> Hmm. Ooh yuck.
>
> Try this...
>
> $ ruby -r time -e 'a=Time.now;p a-Time.parse(a.to_s)'
> 0.00848
> $ ruby -r time -e 'a=Time.now;p a-Time.parse(a.to_s)'
> 0.446575
> $ ruby -r time -e 'a=Time.now;p a-Time.parse(a.to_s)'
> 0.142796
>
> ie. Time#to_s doesn't represent the full precision of the internal
> time format.
>
> Bit of a bummer if you want to round trip an exact timestamp onto disk
> and back.
>
> This does it right...
> $ ruby -e 'a=Time.now;p a-Marshal::load(Marshal::dump(a))'
> 0.0
>
>
> ...but look at whats on disk...
> ruby -e 'a=Time.now;p Marshal::dump(a)'
> "\004\bu:\tTime\rC\347\032\200z\343S\302"
>
> Eeew! Not exactly human friendly.
>
> The following is probably the most elegant way of exactly round
> tripping a time to disk and back in a human readable form?
>
> ruby -w -rtime -e 'a=Time.now;b = a.xmlschema(6);p b;p 
> a-Time.xmlschema(b)'
> "2007-10-26T17:01:08.129059+13:00"
> 0.0
>
>
> Ah well.
>
> John Carter                             Phone : (64)(3) 358 6639
> Tait Electronics                        Fax   : (64)(3) 359 4632
> PO Box 1645 Christchurch                Email : john.carter / tait.co.nz
> New Zealand
>
>
>
>
Hi,
It seems that Time objects are precise to the microsecond, but to_s (and 
to_i) limit the precision to one second.

a= Time.now
b = Time.parse(a.to_s)
a-b   #=> 0.875
a.usec    #=> 875000


I guess you could get a full representation of a Time object by 
combining to_s (or to_i) with #usec

--
Olivier Renaud