email.rb

#require the csv done
#create array done
#extract email address done
#push address into array done
#create a hash done
  #for each address in the array
  #if in the hash, ++
  #if not, set the value to 1
#sort the hash by value
#top 5

require "csv"
addresses = []
address_hash = {}
counter = 0
CSV.foreach "Emails.csv" do |row|
  row.delete(nil)
  row.each do |cell|
    email_address = cell.scan(/\A(?:[\w+\-].?)+@[a-z\d\-]+(?:\.[a-z]+)*\.[a-z]+\z/i)
    addresses.push(*email_address.map(&:downcase))
  end
  counter += 1
  break if counter == 10000
end
#p addresses
addresses.each do |address|
  if address_hash.key?(address)
    address_hash[address] += 1
  else
    address_hash[address] = 1
  end
end
address_hash = Hash[address_hash.sort_by {|_, value| value }.reverse[0..5]]
p address_hash