Documentally
Documentally uses TF-IDF to allow you to easily search and compare text documents.
It's still under development, so the documentation is basically just the tests right now, but an example use would be:
term_lists = [['doc_1', ['foo', 'foo', 'bar']],
['doc_2', ['bar', 'baz', 'baz']],
['doc_3', ['bar', 'baz', 'foo']]]
corpus = Documentally::Corpus.new(term_lists)
query = Documentally::Document.new('query', ['baz'])
corpus.search(query) # => ['doc_2']Installation
gem install documentally