Theorem Flatten Exercise

_Theorem Flatten Exercise README.md

The class DansUtils contains a single method to flatten an array with an undertermined number of nested arrays.

Setup:

1. Create a new test directory
2. Create the two subdirectories: lib and spec
3. Place the above files in their respective directories (see comment on first line of each file)
4. Place the Gemfile the top level directory
5. bundle install --path .bundle

To Test run this command at terminal prompt: $ bundle exec rspec

Which should produce:

3 examples, 0 failures

To Run in ruby console: require './lib/dans_utils.rb' utils = DansUtils.new utils.flatten([array of your choice])

dans_utils.rb

# lib/dans_utils.rb
class DansUtils

  # flatten - Little method to flatten an array of arrays into a single array of atomic elements
  # Sample usage:  dans_flatten(array_to_flatten)
  # Example dans_flatten([1,2,3,[4,5,[6,7]]]) # returns [1, 2, 3, 4, 5, 6, 7]
  def flatten(array, results = [])
    array.each do |element|
      if element.class == Array
        flatten(element, results)
      else
        results << element
      end
    end
    results
  end
end

dans_utils_spec.rb

# spec/dans_utils.rb
require 'dans_utils'

describe DansUtils do

  let(:util)         { DansUtils.new }
  let(:nested_array) { [1,[2,[3,4],5]] }
  let(:flat_array)   { [1, 2, 3, 4, 5] }
  let(:empty_array)  { [] }
  
  context 'flatten' do
      it "returns array of only atomic elements when passed nested arrays" do
        expect(util.flatten(nested_array)).to eq(flat_array)
      end

      it "returns array of only atomic elements when passed flat array" do
        expect(util.flatten(flat_array)).to eq(flat_array)
      end

      it "returns empty array when passed flat array" do
        expect(util.flatten(empty_array)).to eq(empty_array)
      end
  end
  
end

Gemfile

source "https://rubygems.org"

gem "rspec"