From: jzakiya <jzakiya@...>
Date: 2008-03-29T14:05:07+09:00
Subject: Re: numbers of a record in an array

On Mar 28, 11:39 am, jzakiya <jzak...@mail.com> wrote:
> On Mar 27, 10:51 am, Paul Danese <pdan...@Rib-x.com> wrote:
>
>
>
> > If you install the facets gem you can use "frequency"
>
> > e.g.
>
> > >irb
>
> > irb:> require 'rubygems'
> > => false
> > irb:> require 'facets'
> > => true
> > irb:> x = %w[a b d e e rkeke ele e ee e e el d]
> > => ["a", "b", "d", "e", "e", "rkeke", "ele", "e", "ee", "e", "e", "el",
> > "d"]
> > irb:> x.frequency
> > => {"ee"=>1, "a"=>1, "b"=>1, "d"=>2, "e"=>5, "el"=>1, "ele"=>1,
> > "rkeke"=>1}
>
> I installed facets 2.4.0 (the current latest) and tried to use the
> 'frequency' method shown in this example, but in doesn't exist in this
> version of facets.
>
> I did 'ri facets' and it only returned 'Enumerable#frequency'
> This is using Linux (PCLOS) and Ruby 1.8.6-p114.
>
> What version of facets does the 'frequency' method exist in, because
> it isn't in version 2.4.0?

OK, I found what is going on with facets and the 'frequency' method.

In facets 2.3.0 (2008/2/18) 'frequency' is a method under Enumerable,
which got loaded by doing

require 'rubygems'
require 'facets'

The current facets 2.4.0 (2008/3/24) 'frequency' has been moved to the
'probability.rb' file under
the Enumerable module.  So to load 'frequency' under facets 2.4.0 you
must do

require 'rubygems'
require 'facets/enumerable/probability.rb'

I would consider this a bug for breaking prior usage (by hiding the
method in probability.rb).

If you go to http://rubyforge.org/frs/?group_id=804&release_id=20470
and download the tar/zip files for each version you can see the
changes.

This is the facets source for 'frequency'

 def frequency
    #probs = Hash.new(0)
    #each do |e|
    #  probs[e] += 1
    #end
    #probs
    inject(Hash.new(0)){|h,v| h[v]+=1; h}
  end