Euler Project in Ruby - Problem 8

euler8.rb

# Ideone.com can't handle the full integer, our integer n is only the relevant line of the 1000 digit number.  
 
# n = 7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450
n = 70172427121883998797908792274921901699720888093776
 
consec = 5
 
def product integer
  prod = 1
  integer.to_s.length.times { |i| prod *= integer.to_s[i].to_i }
  prod
end
 
array_results = []
(0..n.to_s.length - consec).each do |counter|
  select  = n.to_s[counter..counter + consec - 1]
  prod    = product select
  array_results << prod 
end
 
puts "The max product of #{consec} consecutive digits in the integer n is #{array_results.max}."
 
# Extra, just FYI
index = array_results.index(array_results.max)
puts "(Those #{consec} consecutive digits are #{n.to_s[index..index + consec - 1].to_i}.)"