ruby - 如何使用 ruby​​ 查找字符串中 2 个单词组合的频率？

Question

我一直在使用下面的代码来使用 Ruby 查找字符串中给定单词的频率。我的问题是如何调整它以在给定时间找到 2 个单词的频率。例如：“咩咩咩黑羊”应该返回......

{"baa baa"=>2, "baa black"=>1, "black sheep"=>1}  

代码：

def count_words(string)
  words = string.split(' ')
  frequency = Hash.new(0)
  words.each { |word| frequency[word.downcase] += 1 }
  return frequency
end

Answer 1

str = "baa baa baa black sheep"

count = Hash.new(0)
str.split.each_cons(2) do |words|
  count[ words.join(' ') ] += 1
end
count
# => {"baa baa"=>2, "baa black"=>1, "black sheep"=>1}

Answer 2

def count_words(string)
  words = string.downcase.split(' ')
  frequency = Hash.new(0)
  while words.size >= 2
    frequency["#{words[0]} #{words[1]}"] += 1
    words.shift
  end
  frequency
end