Falling for Ruby: "Holy Crap!" Edition

gistfile1.rb

=begin

Every day I use Ruby I see more and more why people become evangelists.

Take today: I was toying with evaluating different approaches to match two
data sources (API results and a giant local database), and I realized, 
"wait! this is a job for yield!"

So I wrote a pleasant little module with a function that:
- Takes a block which attempts to match an API object to rows in the 
database
- Returns a success rate (defined as the %age of 1-to-1 matches) as well 
as a distribution (e.g., 20 results returned no match, and 40 returned 2 
matches)

PS -- my first gist!

=end


# Example usage
[2] pry(main)> MatchingExperiments.try_approach { |api_restaurant| Restaurant.find_all_by_phone(api_restaurant["phone_number"]).length }
=> {:success_rate=>0.63, :distribution=>{0=>91, 1=>163, 2=>5, 4=>1}}


# matching_experiments.rb
require 'json'

module MatchingExperiments

  # This is my API sampled test data
  APITESTDATA = JSON.parse(File.open("test_data_json_touse.txt","r").read)

  def self.try_approach
    counts = Hash.new
    APITESTDATA.each do |api_restaurant|
      number_of_results = yield(api_restaurant)
      if counts[number_of_results] != nil
        counts[number_of_results] += 1
      else
        counts[number_of_results] = 1
      end
    end
    success_rate = ( counts[1].to_f / counts.inject(0) { |sum,item| sum + item[1] } ).round(2)
    return Hash[success_rate: success_rate, distribution: counts]
  end

end

Awesome! one tiny tip: you can do this:

counts[number_of_results] ||= 0
counts[number_of_results] += 1

instead of this:

if counts[number_of_results] != nil
  counts[number_of_results] += 1
else
  counts[number_of_results] = 1
end

@steveklabnik <3 refactoring!

Thanks, @steveklabnik !

(I had a feeling I could refactor that bit, but was pretty much overloaded with joy by the vaguely-proper use of Ruby closures I'd stumbled my way through.)

RUBYLOVE!!!!

hmmm... i see you went from... highly functional... to....

(pause)...

procedural.

(draws various judgments on your nature)

Ruby values clarity and legibility, and I do too.