From: Logan Capaldo <logancapaldo@...>
Date: 2006-02-09T11:11:21+09:00
Subject: Re: Formatting Numbers


On Feb 8, 2006, at 8:43 PM, HH wrote:

> This has got to be simple but I checked the PickAxe and Google to  
> no avail.
> My guess is that I'm looking for it in terms that don't make sense.
>
> Anyway...
>
> I have a fixnum:
>
> a = 1000
>
> I would like to output it with a comma, such as "1,000". Is there a
> formatting class or something I can use something along these lines
> (thinking from my Java background):
>
> Formatter f = Formatter.new("N0")
> puts f(a)
>
> Any help appreciated.
>
> Thanks,
> Hunter
>
>
>

I dunno know about some kind of builtin format object (I imagine  
maybe the right incantation of sprintf could do it) but heres a  
method (kinda long for what it is, theres probably some regex to do  
it in one fell swoop):

% cat commify.rb
require 'enumerator'
def commify(num)
   str =  num.to_s
   a = []
   str.split(//).reverse.each_slice(3) { |slice| a << slice }
   new_a = []
   a.each do |item|
     new_a << item
     new_a << [","]
   end
   new_a.delete_at(new_a.length - 1)
   new_a.flatten.reverse.join
end

p commify(1000)
p commify(100)
p commify(1_000_000)
p commify(1024)

% ruby commify.rb
"1,000"
"100"
"1,000,000"
"1,024"