Refactoring: Refactorings/Substitute Algorithm

Replace a confusing algorithm with one that is clearer and easier to understand

Mechanics

1. Prepare alternative algorithm
2. Run new algorithm against tests
3. Compare results against existing algorithm
4. Replace old algorithm body with new

Example

Before

def found_friends(people)
  friends = []
  people.each do |person|
    if person == "Don"
      friends << "Don"
    end
    if person == "John"
      friends << "John"
    end
    if person == "Kent"
      friends << "Kent"
    end
  end
  return friends
end

After

def found_friends(people)
  people.select do |person|
    %w(Don John Kent).include? person
  end
end