###About
This library provides high-level Ruby bindings to the Open NLP package, a Java machine learning toolkit for natural language processing (NLP). This gem is compatible with Ruby 1.9.2 and 1.9.3 as well as JRuby 1.7.1. It is tested on both Java 6 and Java 7.
###Installing
First, install the gem: gem install open-nlp. Then, download the JARs and English language models in one package (80 MB).
Place the contents of the extracted archive inside the /bin/ folder of the open-nlp gem (e.g. [...]/gems/open-nlp-0.x.x/bin/).
Alternatively, from a terminal window, cd to the gem's folder and run:
wget http://www.louismullie.com/treat/open-nlp-english.zip
unzip -o open-nlp-english.zip -d bin/
Afterwards, you may individually download the appropriate models for other languages from the open-nlp website.
###Configuring
After installing and requiring the gem (require 'open-nlp'), you may want to set some of the following configuration options.
# Set an alternative path to look for the JAR files.
# Default is gem's bin folder.
OpenNLP.jar_path = '/path_to_jars/'
# Set an alternative path to look for the model files.
# Default is gem's bin folder.
OpenNLP.model_path = '/path_to_models/'
# Pass some alternative arguments to the Java VM.
# Default is ['-Xms512M', '-Xmx1024M'].
OpenNLP.jvm_args = ['-option1', '-option2']
# Redirect VM output to log.txt
OpenNLP.log_file = 'log.txt'
# Set default models for a language.
OpenNLP.use :language###Examples
Simple tokenizer
OpenNLP.load
sent = "The death of the poet was kept from his poems."
tokenizer = OpenNLP::SimpleTokenizer.new
tokens = tokenizer.tokenize(sent).to_a
# => %w[The death of the poet was kept from his poems .]Maximum entropy tokenizer, chunker and POS tagger
OpenNLP.load
chunker = OpenNLP::ChunkerME.new
tokenizer = OpenNLP::TokenizerME.new
tagger = OpenNLP::POSTaggerME.new
sent = "The death of the poet was kept from his poems."
tokens = tokenizer.tokenize(sent).to_a
# => %w[The death of the poet was kept from his poems .]
tags = tagger.tag(tokens).to_a
# => %w[DT NN IN DT NN VBD VBN IN PRP$ NNS .]
chunks = chunker.chunk(tokens, tags).to_a
# => %w[B-NP I-NP B-PP B-NP I-NP B-VP I-VP B-PP B-NP I-NP O]Abstract Bottom-Up Parser
OpenNLP.load
sent = "The death of the poet was kept from his poems."
parser = OpenNLP::Parser.new
parse = parser.parse(sent)
parse.get_text.should eql sent
parse.get_span.get_start.should eql 0
parse.get_span.get_end.should eql 46
parse.get_child_count.should eql 1
child = parse.get_children[0]
child.text # => "The death of the poet was kept from his poems."
child.get_child_count # => 3
child.get_head_index #=> 5
child.get_type # => "S"Maximum Entropy Name Finder*
OpenNLP.load
text = File.read('./spec/sample.txt').gsub!("\n", "")
tokenizer = OpenNLP::TokenizerME.new
segmenter = OpenNLP::SentenceDetectorME.new
ner_models = ['person', 'time', 'money']
ner_finders = ner_models.map do |model|
OpenNLP::NameFinderME.new("en-ner-#{model}.bin")
end
sentences = segmenter.sent_detect(text)
named_entities = []
sentences.each do |sentence|
tokens = tokenizer.tokenize(sentence)
ner_models.each_with_index do |model,i|
finder = ner_finders[i]
name_spans = finder.find(tokens)
name_probs = finder.probs()
name_spans.each_with_index do |name_span,j|
start = name_span.get_start
stop = name_span.get_end-1
slice = tokens[start..stop].to_a
prob = name_probs[j]
named_entities << [slice, model, prob]
end
end
endLoading specific models
Just pass the name of the model file to the constructor. The gem will search for the file in the OpenNLP.model_path folder.
OpenNLP.load
tokenizer = OpenNLP::TokenizerME.new('en-token.bin')
tagger = OpenNLP::POSTaggerME.new('en-pos-perceptron.bin')
name_finder = OpenNLP::NameFinderME.new('en-ner-person.bin')
# etc.Loading specific classes
You may want to load specific classes from the OpenNLP library that are not loaded by default. The gem provides an API to do this:
# Default base class is opennlp.tools.
OpenNLP.load_class('SomeClassName')
# => OpenNLP::SomeClassName
# Here, we specify another base class.
OpenNLP.load_class('SomeOtherClass', 'opennlp.tools.namefind')
# => OpenNLP::SomeOtherClassContributing
Fork the project and send me a pull request! Config updates for other languages are welcome.
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