From: "Ara.T.Howard" <ahoward@...>
Date: 2004-04-02T00:14:33+09:00
Subject: Re: How to get internal state of DateTime in seconds

On 1 Apr 2004, G'irts Kalnins wrote:

> > >How do you get internal state in seconds of DateTime instance? 
> > >Or convert it to Time instance? 
> > >
> > >I want to compare two times with variable precision.
> > >Below is my try to parse time from Common Log Format.
> > >
> > >require 'date'
> > >str1 = '20/Nov/2003:08:08:09 +0200'
> > >str2 = '20/Nov/2003:08:04:09 +0200'
> > >fmt='%d/%b/%Y:%H:%M:%S %Z'
> > >t1 = DateTime.strptime(str1, fmt)
> > >t2 = DateTime.strptime(str2, fmt)
> > >
> > >#what is difference in minutes between these 2 times?
> 
> > Use to_i if you want it as an integer number of seconds
> > 
> > $ ruby -we 'puts Time.now.to_i'
> > => 1080754316
> 
> There is no DateTime#to_i 
> Right now I do like below and it looks ugly to me.
> 
> def dateToTime(str)
>  d = DateTime.strptime(str, fmt='%d/%b/%Y:%H:%M:%S %Z')
>  t = Time.local(d.year, d.month, d.day, d.hour, d.min, d.sec)
>  t
> end


iff
  - your times are a common format
  - your times are within the ranges allowable by Time

both of which appear to be true why not simply parse the time yourself?  this
is plenty clean, especially if it's in instance method of a LogEntry class or
something:


file: logtm.rb

def logtm s
#{{{
  pat = 
    %r|^\s*(\d\d)/(\w\w\w)/(\d\d\d\d):(\d\d):(\d\d):(\d\d)\s+\+(\d\d)(\d\d)\s*$|io

  s = s.to_s
  m = pat.match s
  raise ArgumentError, "<#{ s.inspect }>" unless m

  parts = m.to_a
  raise ArgumentError, "<#{ s.inspect }>" unless parts.size == 9  

  parts.shift
  day, month, year, hour, min, sec, zhour, zmin = parts

  months = %w(jan feb mar apr may jun jul aug sep oct nov dec)
  i = months.index month.downcase
  raise ArgumentError, "<#{ s.inspect }>" unless i
  month = i + 1

  day, month, year, hour, min, sec, zhour, zmin =
    [day, month, year, hour, min, sec, zhour, zmin].map{|x| x.to_i}

  utc = Time.utc year, month, day, hour, min, sec, usec = 0

  t = utc + ((zhour * 60 * 60) + (zmin * 60)) 
#}}}
end

str1 = '20/Nov/2003:08:08:09 +0200'
str2 = '20/Nov/2003:08:04:09 +0200'
t1   = logtm str1
t2   = logtm str2

#what is difference in minutes between these 2 times?
p((t1 - t2).abs / 60.0) # => 4.0


-a
-- 
===============================================================================
| EMAIL   :: Ara [dot] T [dot] Howard [at] noaa [dot] gov
| PHONE   :: 303.497.6469
| ADDRESS :: E/GC2 325 Broadway, Boulder, CO 80305-3328
| URL     :: http://www.ngdc.noaa.gov/stp/
| TRY     :: for l in ruby perl;do $l -e "print \"\x3a\x2d\x29\x0a\"";done 
===============================================================================