From: Rob Biedenharn <Rob@...>
Date: 2009-04-15T10:43:34+09:00
Subject: Re: Date.parse 1.8 vs 1.9


On Apr 14, 2009, at 8:39 PM, Michael Guterl wrote:

> In attempting to make a small library of mine 1.9 compatible I have
> run across an inconsistency in date parsing.
>
> Ruby 1.8:
>>> puts Date.parse("4/12/2009")
> 2009-04-12
>
>>> puts Date.parse("4/30/2009")
> 2009-04-30
>
> Ruby 1.9:
>>> puts Date.parse("4/12/2009")
> 2009-12-04
>
>>> puts Date.parse("4/30/2009")
> ArgumentError: invalid date
>
> I am sure I am not the first person to run across this issue.  What is
> the recommended way for dealing with this?
>
> Best,
> Michael Guterl
>


Probably with Date.strptime rather than Date.parse so you can specify  
a format. I'm not actually that surprised by the 04-12 v. 12-04 since  
the docs say that there are heuristics, but 4/30/2009 ought to be  
unambiguous as 2009 can't be a month or a day and 30 can't be a month.

$ macirb
irb> require 'date'
=> true
irb> puts Date.parse("4/30/2009")
ArgumentError: invalid date
	from /Library/Frameworks/MacRuby.framework/Versions/0.3/usr/lib/ruby/ 
1.9.0/date.rb:1023:in `new_by_frags'
	from /Library/Frameworks/MacRuby.framework/Versions/0.3/usr/lib/ruby/ 
1.9.0/date.rb:1067:in `parse'
	from (irb):2
	from /usr/local/bin/macirb:12:in `<main>'
irb> puts Date.strptime("4/30/2009", "%m/%d/%Y")
2009-04-30
=> nil
irb> RUBY_VERSION
=> "1.9.0"

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com