首先在Ruby中按哈希值对其哈希值进行排序

Question

我正在尝试根据单词按字母顺序出现的次数对文档进行排序，因此在输出时它会看起来像这样。

Unsorted:
'the', '6'
'we', '7'
'those', '5'
'have', '3'

Sorted:
'we', '7'
'the', '6'
'those', '5'
'have', '3'

Answer 1

试试这个：

假设：

a = { 
  'the' => '6', 
  'we' => '7', 
  'those' => '5', 
  'have' => '3', 
  'hav' => '3', 
  'haven' => '3'
}

然后这样做：

b = a.sort_by { |x, y| [ -Integer(y), x ] }

b将如下所示：

[
  ["we", "7"], 
  ["the", "6"], 
  ["those", "5"], 
  ["hav", "3"], 
  ["have", "3"], 
  ["haven", "3"]
]

编辑按反向频率排序。

Answer 2

words = {'the' => 6,'we' => 7,'those' => 5,'have' => 3}
sorted_words = words.sort { |a,b| b.last <=> a.last }
sorted_words.each { |k,v| puts "#{k} #{v}"}

产生

we 7
the 6
those 5
have 3

为了便于比较，您可能希望值​​为整数而不是字符串。

修改

糟糕，忽略了需要按键排序的要求。所以：

words = {'the' => 6,'we' => 7,'those' => 5,'have' => 3,'zoo' => 3,'foo' => 3}
sorted_words = words.sort do |a,b|
  a.last == b.last ? a.first <=> b.first : b.last <=> a.last
end
sorted_words.each { |k,v| puts "#{k} #{v}"}

产生

we 7
the 6
those 5
foo 3
have 3
zoo 3

Answer 3

在散列上使用sort方法时，在比较块中会收到两个元素数组，您可以通过它们在一次传递中进行比较。

hsh = { 'the' => '6', 'we' => '6', 'those' => '5', 'have' => '3'}
ary = hsh.sort do |a,b|
  # a and b are two element arrays in the format [key,value]
  value_comparison = a.last <=> b.last
  if value_comparison.zero?
    # compare keys if values are equal
    a.first <=> b.first
  else
    value_comparison
  end
end
# => [['have',3],['those',5],['the',6],['we',6]]

请注意，结果是一个数组数组，因为哈希在ruby中没有内在顺序

Answer 4

试试这个：

words = {'the' => 6,'we' => 7,'those' => 5,'have' => 3}

words.sort { |(x_k, x_v), (y_k, y_v)| [y_v, y_k] <=> [x_v, x_k]}
#=> [["we", 7], ["the", 6], ["those", 5], ["have", 3]]

Answer 5

histogram = { 'the' => 6, 'we' => 7, 'those' => 5, 'have' => 3, 'and' => 6 }

Hash[histogram.sort_by {|word, freq| [-freq, word] }]
# {
#   'we'    => 7,
#   'and'   => 6,
#   'the'   => 6,
#   'those' => 5,
#   'have'  => 3
# }

注意：这假定您使用数字来存储数字。在您的数据模型中，您似乎使用字符串来存储数字。我不知道你为什么要这样做，但如果你做想要这样做，你显然必须在排序之前将它们转换为数字，然后再转换回字符串。

此外，这假设Ruby 1.9。在Ruby 1.8中，哈希不是有序的，所以你不能将排序后的结果转换回哈希，因为这会丢失排序信息，你必须将它保存为数组。

Answer 6

word_counts = {
        'the' => 6,
        'we' => 7,
        'those' => 5,
        'have' => 3,
        'and' => 6
};

word_counts_sorted = word_counts.sort do
        |a,b|
        # sort on last field descending, then first field ascending if necessary
        b.last <=> a.last || a.first <=> b.first
end

puts "Unsorted\n"
word_counts.each do
        |word,count|
        puts word + " " + count.to_s
end

puts "\n"
puts "Sorted\n"
word_counts_sorted.each do
        |word,count|
        puts word + " " + count.to_s
end

Answer 7

1.9.1

>> words = {'the' => 6,'we' => 7, 'those' => 5, 'have' => 3}
=> {"the"=>6, "we"=>7, "those"=>5, "have"=>3}              
>> words.sort_by{ |x| x.last }.reverse
=> [["we", 7], ["the", 6], ["those", 5], ["have", 3]]