output

count_frequency.rb

def count_frequency(word_list)
  counts = Hash.new(0)
  for word in word_list
    counts[word] += 1
  end
 counts
end

gistfile2.txt

e: e
t: t
k: k
a: a
c: c

ugly_word_count.rb

require_relative 'words_from_string.rb'
require_relative 'count_frequency.rb'

raw_text = %{
  The problem breaks down into two parts. First, given some test as a 
  string, return a list of words. That sounds like an array. Then, build a
  count for each distinct word. That sounds like a use for a hash---we can
  index it with the word and use the corresponding entry to keep a count.
}

word_list = words_from_string(raw_text)
counts    = count_frequency(word_list)
sorted    = counts.sort_by {|word, count| count}
top_five  = sorted.last(5)

for i in 0...5
  word = top_five[i][0]
  count = top_five[i][0]
  puts "#{word}: #{count}"
end

words_from_string.rb

def words_from_string(string)
  string.downcase.scan(/[\w']+/)
end