How do I format a date in ruby to include "rd" as in "3rd"

Question

I want to format a date object so that I can display strings such as "3rd July" or "1st October". I can't find an option in Date.strftime to generate the "rd" and "st". Any one know how to do this?

Shaven

Answer 1

I'm going to echo everyone else, but I'll just encourage you to download the activesupport gem, so you can just use it as a library. You don't need all of Rails to use ordinalize.

% gem install activesupport
...
% irb 
irb> require 'rubygems'
#=>  true
irb> require 'activesupport'
#=>  true
irb> 3.ordinalize
#=>  "3rd"

Breakage

Good point. You can also get this functionality from the facets (facets.rubyforge.org) library - require 'facets' or, for just this method, require 'facets/integer/ordinal' – Abductor

How do we extract just the ordinalization? I want to do 3<span>th</span> – Islander

Volte: 3.ordinalize.sub(/\w+/, '<span>\0</span>') – Breakage

There's a much easier way to get what you want without manipulating the day integer by hand: date.to_s(:long_ordinal). See: api.rubyonrails.org/classes/Date.html#method-i-to_formatted_s – Maculation

Answer 2

Unless you're using Rails, add this ordinalize method (code shamelessly lifted from the Rails source) to the Fixnum class

class Fixnum
  def ordinalize
    if (11..13).include?(self % 100)
      "#{self}th"
    else
      case self % 10
        when 1; "#{self}st"
        when 2; "#{self}nd"
        when 3; "#{self}rd"
        else    "#{self}th"
      end
    end
  end
end

Then format your date like this:

> now = Time.now
> puts now.strftime("#{now.day.ordinalize} of %B, %Y")
=> 4th of July, 2009

Collaborate

Note that this answer is a bit outdated. Here's how it looks like now and here's the extension to the Integer class. – Endodontics

Answer 3

created_at.strftime("#{created_at.day.ordinalize} of %m, %y")

Will produce "4th of July, 2009"

Zollie

I had to add a # in front of the { but this worked a treat Thanks! – Hurlburt

how would you ordinalize the string variables? I need to turn %m for example. – Trimmer

This is nice when you need to use the atypical "4th of July" format but there's no need to ordinalize by hand if you're using the conventional "July 4th, 2009": created_at.to_date.to_s(:long_ordinal). – Maculation

Answer 4

I don't think Ruby has it, but if you have Rails, try this:-

puts 3.ordinalize #=> "3rd"

Deleterious

It's also available in Facets. – Thermostatics

Answer 5

Seems I'm revisiting this topic for a third time, so I've updated my gist with some extra comments / usage.

https://gist.github.com/alterisian/4154152

Cheers, Ian.

Spectrum

Answer 6

I don't know if it makes it that much (any?) faster than switch-case, but I made a constant with the endings:

DAY_ENDINGS = ["th", "st", "nd", "rd", "th", "th", "th", "th", "th", "th", "th", "th", "th", "th", "th", "th", "th", "th", "th", "th", "th", "st", "nd", "rd", "th", "th", "th", "th", "th", "th", "th", "st"]

Then just used it like:

DAY_ENDINGS[date.mday]

As I wanted the ending inside a

<span>th</span>

Simsar

Answer 7

require 'activesupport'
1.ordinal => 'st'
1.ordinalize => '1st'

Council

Answer 8

require 'time'

H = Hash.new do |_,k|
  k +
  case k
  when '1', '21', '31'
    'st'
  when '2', '22'
    'nd'
  when '3', '23'
    'rd'
  else
    'th'
  end
end 

def fmt_it(time)
  time.strftime("%A %-d, %-l:%M%P").sub(/\d+(?=,)/, H) 
end

fmt_it(Time.new)
  #=> "Wednesday 9th, 1:36pm"

fmt_it(Time.new + 3*24*60*60)
  #=> "Saturday 12th, 3:15pm"

I have used the form of String#sub (one could use sub!) that takes a hash (H) as its second argument.

The regular expression used by sub reads "match one or more digits followed by a comma". (?=,) is a positive lookahead.

I created the (empty) hash H using the form of Hash::new that takes a block. This simply means that if H does not have a key k, H[k] returns the value computed by the block. In this case the hash is empty so the block always returns the value of interest. The block takes two arguments, the hash (here H) and the key being evaluated. I've represented the former with an underscore, signalling that it is not used by the block). Some examples:

H['1']  #=>  "1st" 
H['2']  #=>  "2nd" 
H['3']  #=>  "3rd" 
H['4']  #=>  "4th" 
H['9']  #=>  "9th" 
H['10'] #=> "10th" 
H['11'] #=> "11th" 
H['12'] #=> "12th" 
H['13'] #=> "13th" 
H['14'] #=> "14th" 
H['22'] #=> "22nd" 
H['24'] #=> "24th" 
H['31'] #=> "31st" 

See Time#strftime for formatting directives.

Swinger