From: Mike Stok <mike@...>
Date: 2013-07-03T07:33:25+09:00
Subject: Re: How can I add minutes,seconds and hours to a DateTime object?


On 2013-07-02, at 3:41 PM, Love U Ruby <lists@ruby-forum.com> wrote:

> finally I came up with as below :
> 
> require 'date'
> 
> text_t = '2:12:03 PM ET'
> dt = DateTime.parse(text_t, '%I:%M %p %Z')
> # => #<DateTime: 2013-07-03T14:12:03+00:00 
> ((2456477j,51123s,0n),+0s,2299161j)>
> dt.to_s
> # => "2013-07-03T14:12:03+00:00" # !> invalid offset is ignored
> dh = Date._strptime(dt.to_s,'%Y-%m-%dT%H:%M:%S%z')
> # => {:year=>2013,
> #     :mon=>7,
> #     :mday=>3,
> #     :hour=>14,
> #     :min=>12,
> #     :sec=>3,
> #     :zone=>"+00:00",
> #     :offset=>0}
> 
> dh[:hour] += 30 # => 44
> dh
> # => {:year=>2013,
> #     :mon=>7,
> #     :mday=>3,
> #     :hour=>44,
> #     :min=>12,
> #     :sec=>3,
> #     :zone=>"+00:00",
> #     :offset=>0}
> 
> dh.values[0..-2].join(" ")
> # => "2013 7 3 44 12 3 +00:00"
> DateTime.ordinal(*dh.values[0..-3])
> # => #<DateTime: 2013-01-07T03:44:12+00:00 
> ((2456300j,13452s,0n),+0s,2299161j)>
> 
> Please suggest me if any wrong calculation has been made by me? Please
> 
> Thanks
> 
> -- 
> Posted via http://www.ruby-forum.com/.

It does seem odd that 30 hours after 2013-07-03T14:12:03+00:00 is 2013-01-07T03:44:12+00:00, and you do seem to be doing a lot of work to add 30 hours - looking a the code there is a lot of "noise".

If I look at the documentation for DateTime then I see I can use + to add a fractional number of days, http://www.ruby-doc.org/stdlib-2.0/libdoc/date/rdoc/Date.html#method-i-2B , so:

ratdog:tmp mike$ pry
[1] pry(main)> require 'date'
=> false
[2] pry(main)> dt = DateTime.parse('2:12:03 PM ET', '%I:%M %p %Z')
=> #<DateTime: 2013-07-02T14:12:03+00:00 ((2456476j,51123s,0n),+0s,2299161j)>
[3] pry(main)> dt + (30.0 / 24) # days
=> #<DateTime: 2013-07-03T20:12:03+00:00 ((2456477j,72723s,0n),+0s,2299161j)>

Hope this helps,

Mike

-- 

Mike Stok <mike@stok.ca>
http://www.stok.ca/~mike/

The "`Stok' disclaimers" apply.