From: Robert Klemme <shortcutter@...>
Date: 2008-12-06T21:18:52+09:00
Subject: Re: Proximity searches in Ruby

On 06.12.2008 00:29, Ilan Berci wrote:
> No proximity searches with 1.8.. you would need a full fledged text 
> search engine such as lucerne, sphinx for that type of capability

Or, depending on requirements (especially performance) cook your own.

def proximity_search(text, distance, w1, w2)
   w1 = w1.downcase
   w2 = w2.downcase
   index1 = []
   index2 = []

   text.scan(/\w+/).each_with_index do |w,idx|
     case
       when w1 == w.downcase
         index1 << idx
       when w2 == w.downcase
         index2 << idx
     end
   end

   found = false

   index1.each do |i1|
     index2.each do |i2|
       if (i1 - i2).abs <= distance
         found = true
         yield i1, i2 if block_given?
       end
     end
   end

   found
end

text = <<EOT
Hello world, how are you today? I said "Hello"
to the other guy but he would not answer although
all the world could hear me.
EOT

proximity_search text, 3, "hello", "World" do |a,b|
   printf "Found at positions %3d and %3d\n", a, b
end

p proximity_search(text, 3, "hello", "World")

Cheers

	robert