Eric Milford :: Web Developer & Food Advocate

Ordinalized Dates w/ Ruby on Rails

Posted by Eric Milford on October 16, 2009

Tagged with Ruby on Rails

Disqus Comments

December 31st, 1980. It's a common enough date format that I'm surprised a "%o" format placeholder or similar isn't available for Ruby's strftime method.


1 >> d = DateTime.now

2 => Fri, 16 Oct 2009 15:11:49 -0400

3 

4 >> date.strftime('%B %o, %Y')

5 => "October o, 2009" # Uh oh

6 

7 >> date.strftime('%B %o, %Y')

8 => "October 16th, 2009" # I wish

The following line of code is what I've seen most often referenced as a solution. It's quick and effective, but the double call to date feels unnatural and not very Rails-like.


1 date.strftime("%B #{date.day.ordinalize}, %Y")

For the Ruby-only crowd, you might very well be stuck. As I mentioned above, Ruby's standard method for date formatting does not support an ordinal date. In Rails, however, the convention is to place the DATE_FORMATS inside of an initializer, config/initializer/time_formats.rb.


 1 ActiveSupport::CoreExtensions::Time::Conversions::DATE_FORMATS.merge!(

 2    :datetime_military => '%Y-%m-%d %H:%M',

 3    :datetime          => '%Y-%m-%d %I:%M%P',

 4    :ordinalize        => lambda { |time| time.strftime("%a %b #{time.day.ordinalize}") }

 5 )

 6 

 7 >> d = DateTime.now

 8 => Fri, 16 Oct 2009 15:11:49 -0400

 9 

10 >> d.to_s(:ordinalize)

11 => "Fri Oct 16th"