如何根据 Ruby 中的值拆分哈希？
我在 Ruby 中有一个散列，它存储字符串的词频，以词作为键，频率作为值。
words = a_string.split(/ /)
freqs = Hash.new(0)
words.each { |word| freqs[word] += 1 }
freqs = freqs.sort_by {|x,y| y }
freqs.reverse!
freqs.each do |word, freq|
puts word+' '+freq.to_s
end
我读过哈希迭代器以随机顺序返回哈希，但这似乎到目前为止都有效。
现在我需要 freqs 哈希以仅包含 20 个最常见的单词。我该怎么做？感谢您的阅读。
I have a hash in Ruby that is storing the word frequency of a string, with the word as the key and the frequency as the value.
words = a_string.split(/ /)
freqs = Hash.new(0)
words.each { |word| freqs[word] += 1 }
freqs = freqs.sort_by {|x,y| y }
freqs.reverse!
freqs.each do |word, freq|
puts word+' '+freq.to_s
end
I've read that hash iterators return the hash in a random order, but this seems to work so far.
Now I need to freqs hash to only contain the 20 most frequent words. How can I do this? Thanks for reading.
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正如您可能已经看到的，它保持排序的原因是因为您调用 < code>Enumerable#sort_by 将您的
Hash更改为Array。从该方法的文档中：一旦你有了排序后的数组，你就可以使用
Array#first< /code>获取前 20 名：如果需要，您可以在结果上使用
to_hash将其返回到Hash，但它不会不再排序。As you've probably seen, the reason it stays sorted is because your call to
Enumerable#sort_bychanges yourHashinto anArray. From the documentation for that method:Once you have your sorted array, you could just use
Array#firstto get the top 20:If you want, you could use
to_hashon the result to return it back to aHash, but it will no longer be sorted.