CombinationExtractor

Exctract keyed patterns hash to combination keyed hash.

Convert this hash:

{
  fruit: ['apple', 'orange'],
  city: ['NewYork', 'London', 'Tokyo']
}

To this:

[
  {:fruit=>"apple", :city=>"NewYork"},
  {:fruit=>"apple", :city=>"London"},
  {:fruit=>"apple", :city=>"Tokyo"},
  {:fruit=>"orange", :city=>"NewYork"},
  {:fruit=>"orange", :city=>"London"},
  {:fruit=>"orange", :city=>"Tokyo"}
]

Installation

Add this line to your application's Gemfile:

gem 'combination-extractor'

And then execute:

$ bundle

Or install it yourself as:

$ gem install combination-extractor

Usage

Example

CombinationExtractor.extract({fruit: ['apple', 'orange'], city: ['NewYork', 'London', 'Tokyo']})
=> [{:fruit=>"apple", :city=>"NewYork"}, {:fruit=>"apple", :city=>"London"}, {:fruit=>"apple", :city=>"Tokyo"},
    {:fruit=>"orange", :city=>"NewYork"}, {:fruit=>"orange", :city=>"London"}, {:fruit=>"orange", :city=>"Tokyo"}]

Example for rspec

def example_similar_to(user_hash)
  user_hash[:birthday] == Time.new(1988, 12, 30) &&
    user_hash[:gender] == :male
end

describe 'About example example_similar_to method' do
  let(:nickname) { nil }
  let(:gender) { nil }
  let(:birthday) { nil }
  let(:user) { { nickname: nickname, gender: gender, birthday: birthday } }

  user_condition = {
    nickname: ['John', 'Ken', 'Jessie'],
    gender: [:female, :male],
    birthday: [Time.new(1988, 12, 30), Time.now]
  }
  # Get 2*2*3 = 12 patterns
  pattern_list = CombinationExtractor.extract(user_condition)

  pattern_list.each do |pattern|
    describe "user who is #{pattern.to_s}" do
      # NOTE: Set pattern to lazy evaluated variable
      pattern.each { |key, value| let(key) { value } }

      should_value = pattern[:gender] == :male && pattern[:birthday] == Time.new(1988, 12, 30)
      it "should return #{should_value}" do
        expect(example_similar_to(user)).to eq(should_value)
      end
    end
  end
end

bundle exec rspec returns this:

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/akiroom/combination-extractor.

License

The gem is available as open source under the terms of the MIT License.