嵌套哈希和

Question

我有这个哈希

{
    19132=>{
        :occurences=>34,
        :name=>"bar"
    },
    19133=>{
        :occurences=>19,
        :name=>"foo"
    }
}

我想在每个键（19132 和 19133）上找到新键（为什么不是 total）中出现次数 (34+19) 的添加。

我有这样的东西：

my_hash = {19132=>{:occurences=>34, :name=>"bar"}, 19133=>{:occurences=>19, :name=>"foo"}}
my_hash.values.inject{|memo, el| memo.merge(el){|k, old_v, new_v| old_v + new_v if k.is_a?(Numeric)}}

我找到了一些帮助 Here，但我无法进行合并。我什至不知道这个方法能不能解决我的问题。

Answer 1

我尝试分两步实现它：查找总数和合并总数。

hash = {19132=>{:occurences=>34, :name=>"bar"}, 19133=>{:occurences=>19, :name=>"foo"}}

total = hash.collect(&:first).sum
# => 38265

hash.each{|h| h[1].merge!({"total" => total})}
# => {19132=>{:occurences=>34, :name=>"bar", "total"=>38265}, 19133=>{:occurences=>19, :name=>"foo", "total"=>38265}}

Answer 2

首先，遍历所有内部哈希并计算总数：

total = h.values.inject(0) { |total, hash| total + hash[:ocurrences] }

然后，将总数添加到内部哈希值中：

h.keys.each{|k| h[k][:total] = total}

Answer 3

sum = h.values.inject(0) {|sum, h| sum + h[:occurences] }
# => 53 
h.map {|k, v| v[:total] = sum; [k,v]}.to_h
# => { 19132=>{:occurences=>34, :name=>"bar", :total=>53},
#      19133=>{:occurences=>19, :name=>"foo", :total=>53} }

Answer 4

你可以这样做：

tot = h.each_value.reduce(0) { |t, g| t + g[:occurrences] }
h.merge(h) { |*_,g| g.merge("total"=>tot) }
  # => {19132=>{:occurrences=>34, :name=>"bar", "total"=>53},
  #     19133=>{:occurrences=>19, :name=>"foo", "total"=>53}}

这不会改变原始哈希值：

h #=> {19132=>{:occurrences=>34, :name=>"bar"},
  #    19133=>{:occurrences=>19, :name=>"foo"}}

如果您想原地更改h：

h.merge!(h) { |*_,g| g.merge!("total"=>tot) }

有效，但是：

h.each_value { |g| g["total"] = tot }

更好。

嵌套哈希和

Nested Hash sum

ruby

hash