From: Jan Svitok <jan.svitok@...>
Date: 2007-01-08T03:03:55+09:00
Subject: Re: Ruby Cookbook question

On 1/6/07, Bharat Ruparel <bruparel@mercury.com> wrote:
> 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.

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.

2. 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).