Ferret talk - Sep 2006 - Querying against numeric fields? e.g. price:( >= min_price)

Using acts_as_ferret I''m trying to do a query like:

active:(true) title|body:(#{params[:s]}) product_price:( >= 
#{params[:min]})


Where I want to return only the active products that contain the search 
term in the title or body and has a minimum price >= params[:min]

I''m finding that even though I''m indexing the product price as
an
integer (so no .00 to cause confusion) I''m getting results in the 50 
value range as well as 500 if I set the min price as 500. I presume 
ferret is doing the price as a string comparison, but is there any way 
to make it do a numeric match?

Thanks

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On 9/13/06, Tom Beddard <tom at subblue.com>
wrote:
> Using acts_as_ferret I''m trying to do a query like:
>
> active:(true) title|body:(#{params[:s]}) product_price:( >>
#{params[:min]})
>
>
> Where I want to return only the active products that contain the search
> term in the title or body and has a minimum price >= params[:min]
>
> I''m finding that even though I''m indexing the product
price as an
> integer (so no .00 to cause confusion) I''m getting results in the
50
> value range as well as 500 if I set the min price as 500. I presume
> ferret is doing the price as a string comparison, but is there any way
> to make it do a numeric match?
>
> Thanks
Hi Tom,

You need to pad all numbers to a fixed width when adding them to the
index as well as when querying the index. Usually you''d write the code
to do this yourself. I''ve recently come up with another way to do
this.

    require ''ferret''

    module Ferret::Analysis
      class IntegerTokenizer
        def initialize(num, width)
          @num = num.to_i
          @width = width
          @done = false
        end
        def next
          if @done
            return nil
          else
            @done = true
            puts Token.new("%0#{@width}d" % @num, 0, @width)
            return Token.new("%0#{@width}d" % @num, 0, @width)
          end
        end
        def text=(text)
          @num = text.to_i
          @done = false
        end
      end

      class IntegerAnalyzer
        def initialize(width)
          @width = width
        end
        def token_stream(field, input)
          return IntegerTokenizer.new(input, @width)
        end
      end
    end

    include Ferret::Analysis
    analyzer = PerFieldAnalyzer.new(StandardAnalyzer.new)
    analyzer[:num] = IntegerAnalyzer.new(5)

    index = Ferret::Index::Index.new(:analyzer => analyzer)
    docs = [
      {:num => 1,    :data => "yes"},
      {:num => 1,    :data => "no"},
      {:num => 10,   :data => "yes"},
      {:num => 10,   :data => "no"},
      {:num => 100,  :data => "yes"},
      {:num => 100,  :data => "no"},
      {:num => 1000, :data => "yes"},
      {:num => 1000, :data => "no"}
    ]

    docs.each { |d| index << d }

    puts index.process_query(''data:yes AND num:[10 100]'')
    puts index.search(''data:yes AND num:[10 100]'')

This will only work with the working copy of Ferret from the
subversion repository. I''m still not convinced that this is the best
way to do it.

Cheers,
Dave

Hi, David.

Can you tell me where to include your codes for integration with
Rails(acts_as_ferret)?
I just want to pad 0''s to do numeric comparision

I am pretty new to Rails and Ferret.

Thanks.
Yaxm


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This doesn''t work because "10" is used.
>     puts index.process_query(''data:yes AND num:[10 100]'')
>     puts index.search(''data:yes AND num:[10 100]'')
One must pad the integer with zero''s just like the analyzer:

puts index.process_query(''data:yes AND num:[00010 00100]'')
puts index.search(''data:yes AND num:[00010 00100]'')

To use this in a Rails app:
include the IntegerAnalyzer defnition in a file.

then require the file in your model.

inside your model class:

  include Ferret::Analysis
  analyzer = PerFieldAnalyzer.new(StandardAnalyzer.new)
  analyzer[:num] = IntegerAnalyzer.new(5)
  analyzer[:blah_field] = IntegerAnalyzer.new(5)

  acts_as_ferret(
      {:fields => [:blah_field] }
       ,  {:analyzer => analyzer}

David Balmain wrote:
> On 9/13/06, Tom Beddard <tom at subblue.com> wrote:
>> integer (so no .00 to cause confusion) I''m getting results in
the 50
>> value range as well as 500 if I set the min price as 500. I presume
>> ferret is doing the price as a string comparison, but is there any way
>> to make it do a numeric match?
>>
>> Thanks
> 
> Hi Tom,
> 
> You need to pad all numbers to a fixed width when adding them to the
> index as well as when querying the index. Usually you''d write the
code
> to do this yourself. I''ve recently come up with another way to do
> this.
> 
>     require ''ferret''
> 
>     module Ferret::Analysis
>       class IntegerTokenizer
>         def initialize(num, width)
>           @num = num.to_i
>           @width = width
>           @done = false
>         end
>         def next
>           if @done
>             return nil
>           else
>             @done = true
>             puts Token.new("%0#{@width}d" % @num, 0, @width)
>             return Token.new("%0#{@width}d" % @num, 0, @width)
>           end
>         end
>         def text=(text)
>           @num = text.to_i
>           @done = false
>         end
>       end
> 
>       class IntegerAnalyzer
>         def initialize(width)
>           @width = width
>         end
>         def token_stream(field, input)
>           return IntegerTokenizer.new(input, @width)
>         end
>       end
>     end
> 
>     include Ferret::Analysis
>     analyzer = PerFieldAnalyzer.new(StandardAnalyzer.new)
>     analyzer[:num] = IntegerAnalyzer.new(5)
> 
>     index = Ferret::Index::Index.new(:analyzer => analyzer)
>     docs = [
>       {:num => 1,    :data => "yes"},
>       {:num => 1,    :data => "no"},
>       {:num => 10,   :data => "yes"},
>       {:num => 10,   :data => "no"},
>       {:num => 100,  :data => "yes"},
>       {:num => 100,  :data => "no"},
>       {:num => 1000, :data => "yes"},
>       {:num => 1000, :data => "no"}
>     ]
> 
>     docs.each { |d| index << d }
> 
>     puts index.process_query(''data:yes AND num:[10 100]'')
>     puts index.search(''data:yes AND num:[10 100]'')
> 
> This will only work with the working copy of Ferret from the
> subversion repository. I''m still not convinced that this is the
best
> way to do it.
> 
> Cheers,
> Dave

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