From: ara.t.howard@...
Date: 2006-10-25T23:04:22+09:00
Subject: Re: Reopening Classes

On Wed, 25 Oct 2006, anthony.green@bbc.co.uk wrote:

> Can someone offer an explaination as to what I'm encountering here..
>
> ......................................................................................
> This code doesn't work...
>
> class Time
>  def <=>(other_time)
>    self.strftime("%H%M%S%Y%m%d").to_i <=>
> other_time.strftime("%H%M%S%Y%m%d").to_i
>  end
> end
>
> first = Time.local(2006, 10, 21)
> last = Time.local(2006, 10, 27)
>
> time_slots = []
> range = first..last
> range.step(1.hour) do |day_slot|
>  time_slots << day_slot
> end
>
> time_slots.sort
>
> ......................................................................................
>
> the time_slots array isn't populating properly
> ......................................................................................
>
> This does
>
> first = Time.local(2006, 10, 21)
> last = Time.local(2006, 10, 27)
>
> time_slots = []
> range = first..last
> range.step(1.hour) do |day_slot|
>  time_slots << day_slot
> end
>
> class Time
>  def <=>(other_time)
>    self.strftime("%H%M%S%Y%m%d").to_i <=>
> other_time.strftime("%H%M%S%Y%m%d").to_i
>  end
> end
>
> time_slots.sort
>
> ......................................................................................

i see you already got an answer, but you might want to know about this idiom:

   harp:~ > cat a.rb
   lt = lambda{|*a| Time.local *a}
   hr = 3600
   times = []
   fields = %w( hour min sec year month day )

   ( lt[2006, 10, 21] .. lt[2006, 10, 23] ).step(hr){|t| times << t}

   sorted = times.sort_by{|t| fields.map{|f| t.send f}}

   puts sorted.first(16)



   harp:~ > ruby a.rb
   Sat Oct 21 00:00:00 MDT 2006
   Sun Oct 22 00:00:00 MDT 2006
   Mon Oct 23 00:00:00 MDT 2006
   Sat Oct 21 01:00:00 MDT 2006
   Sun Oct 22 01:00:00 MDT 2006
   Sat Oct 21 02:00:00 MDT 2006
   Sun Oct 22 02:00:00 MDT 2006
   Sat Oct 21 03:00:00 MDT 2006
   Sun Oct 22 03:00:00 MDT 2006
   Sat Oct 21 04:00:00 MDT 2006
   Sun Oct 22 04:00:00 MDT 2006
   Sat Oct 21 05:00:00 MDT 2006
   Sun Oct 22 05:00:00 MDT 2006
   Sat Oct 21 06:00:00 MDT 2006
   Sun Oct 22 06:00:00 MDT 2006
   Sat Oct 21 07:00:00 MDT 2006


the basic idea of

   fields = %w( one two three )

   list.sort_by{|elem| fields.map{|f| elem.send f}}

is powerful.


regards.

-a
-- 
my religion is very simple.  my religion is kindness. -- the dalai lama