Ruby Cookbook question

Ruby
1

Hello All,
This is a question from Ruby Cookbook by Lucas Carlson & Leonard
Richardson, Oreilly Publication. Recipe number 1.20 in Chapter 1 on
page 37.
As instructed in the book, I am trying to use the classifer gem to do
Bayesian Analysis. It advises me to install the classifer gem by using
the ‘gem install classifer’ command. gem asks me if I want to install
the stemmer gem as a dependency, I say yes and it installs it.

Next, I am trying to check if everything works by running a snippet out
of the README file from the classifer gem install directory as follows:

test.rb which contains the following lines of code:

require 'classifier'
b = Classifier::Bayes.new 'Interesting', 'Uninteresting'
b.train_interesting "here are some good words. I hope you love them"
b.train_uninteresting "here are some bad words, I hate you"
b.classify "I hate bad words and you" # returns 'Uninteresting'

When I run it, I get the following error:

ruby test.rb
Notice: for 10x faster LSI support, please install
http://rb-gsl.rubyforge.org/
c:/ruby/lib/ruby/gems/1.8/gems/classifier-1.3.0/lib/classifier/bayes.rb:95:in
method_missing': undefined method stem’ for “here”:String
(NoMethodError)
from
c:/ruby/lib/ruby/gems/1.8/gems/classifier-1.3.0/lib/classifier/extensions/word_hash.rb:32:in
each' from c:/ruby/lib/ruby/gems/1.8/gems/classifier-1.3.0/lib/classifier/extensions/word_hash.rb:32:in word_hash_for_words’
from
c:/ruby/lib/ruby/gems/1.8/gems/classifier-1.3.0/lib/classifier/extensions/word_hash.rb:20:in
word_hash' from c:/ruby/lib/ruby/gems/1.8/gems/classifier-1.3.0/lib/classifier/bayes.rb:26:in train’
from (eval):1:in method_missing' from c:/ruby/lib/ruby/gems/1.8/gems/classifier-1.3.0/lib/classifier/bayes.rb:95:in eval’
from
c:/ruby/lib/ruby/gems/1.8/gems/classifier-1.3.0/lib/classifier/bayes.rb:95:in
method_missing' from c:/ruby/lib/ruby/gems/1.8/gems/classifier-1.3.0/lib/classifier/bayes.rb:95:in each’
from
c:/ruby/lib/ruby/gems/1.8/gems/classifier-1.3.0/lib/classifier/bayes.rb:95:in
`method_missing’
from test.rb:3
Exit code: 1

I contacted the author, Lucas Carlson, concerning this and he advised me
to install the stemmer gem by doing ‘gem install stemmer’ command. I
have done that already by answering Yes to the question by gem installer
if the dependency gem should be installed? I can also see the stemmer
gem that has been installed in the gems directory. Mind you, this
happens both in Linux and Windows operating systems, therefore, there is
something that I must be overlooking. I haven’t heard back from the
author. Therefore, I am posting this question here on the forum to see
if anyone can help.

Thanks in advance.

Bharat

2

On 1/6/07, Bharat R. [email protected] wrote:

of the README file from the classifer gem install directory as follows:

c:/ruby/lib/ruby/gems/1.8/gems/classifier-1.3.0/lib/classifier/extensions/word_hash.rb:32:in
`eval’

Exit code: 1

I contacted the author, Lucas Carlson, concerning this and he advised me
to install the stemmer gem by doing ‘gem install stemmer’ command. I
have done that already by answering Yes to the question by gem installer
if the dependency gem should be installed? I can also see the stemmer
gem that has been installed in the gems directory. Mind you, this
happens both in Linux and Windows operating systems, therefore, there is
something that I must be overlooking. I haven’t heard back from the
author. Therefore, I am posting this question here on the forum to see
if anyone can help.

  1. You can check you have the stemmer installed ok by running the
    following script, outside of the gems dir:

require ‘rubygems’
require ‘stemmer’
puts ‘here’.stem #=> ‘here’

if it raises an exception (method missing or similar), the stemmer is
not installed correctly.

  1. make sure that rubygems are required in the test script (either
    directly or by -rubygems paramter to ruby or by using RUBYOPT
    environment variable AND that stemmer is required somewhere (you can
    fix it temporarily by running ruby -rubygems -rstemmer test.rb - if
    that works, there’s missing require line somewhere).
3

Thank you.
As you suggested, I checked if stemmer was installed correctly. It was.
Then I added the line
require ‘stemmer’ to my code and it worked.
Regards,
Bharat