largestproduct.rb

class LargestProduct

  def self.produce(digits,consec)
    how_many = digits.length - (consec - 1)
    start_index = 0
    compare = {}
    how_many.times do
      section = digits.slice(start_index,consec).split("")
      p = section.inject do |result,current|
        result.to_i * current.to_i
      end
      compare[p] = section
      start_index += 1
    end
    largest = compare.max_by{|k,v| k }
    puts "The largest product is #{largest[0]} from the numbers #{largest[1].join(",")}."
  end

end

LargestProduct.produce('75438',3)
LargestProduct.produce('7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450',13)