term_extract - Term Extract

term_extract extracts proper nouns (named things like 'Manchester United') and ordinary nouns (like 'event') from text documents.

An example extracting terms from a piece of content:

require 'term_extract'

content = <<DOC
Business Secretary Vince Cable will stay in cabinet despite
"declaring war" on Rupert Murdoch, says Downing Street.
DOC

terms = TermExtract.extract(content)

The #extract method takes an (optional) options hash, that allows the term extractor behaviour to be modified. The following options are available:

• min_occurance - The minimum number of times a single word term must occur to be included in the results, default 3
• min_terms - Always include multiword terms that comprise more than @min_terms words, default 2
• types - Extract proper nouns (:nnp) or nouns (:nn) or both (:all), default :all
• include_tags - Include the extracted POS tags in the results, default false
• collapse_terms - Remove shorter terms that are part of larger ones, default true

Sample usage:

terms = TermExtract.extract(content, :types => :nnp, :include_tags => true)

By default, the term extractor attempts to extract both ordinary nouns and proper nouns, this behaviour can be configured using the #types option and specifying :all (for both), :nn (for ordinary nouns) or :nnp (for proper nouns). These codes correspond to the relevent POS tags used during the term extraction process. Sample usage is shown below:

terms = TermExtract.extract(content, :types => :nnp)

There is a command line tool that can be used for testing the term extractor. It is best used in conjunction with another tool to extract the relevent content (e.g. pismo) :

pismo http://www.bbc.co.uk/news/uk-politics-12085506 body | ruby -rubygems -e 'puts YAML.parse($stdin.read)[:body].value' | ./term-extract nnp | ruby -rubygems -e 'puts YAML.load($stdin.read)'

• Fork the project.
• Make your feature addition or bug fix.
• Add tests for it. This is important so I don't break it in a future version unintentionally.
• Commit, do not mess with Rakefile, version, or history as it's handled by Jeweler.
• Send me a pull request. I may or may not accept it.

The algorithm and extraction code is based on the original python code at:

http://pypi.python.org/pypi/topia.termextract/

GPL v3 - See LICENSE.txt for details. Copyright (c) 2010, Rob Lee