将散列转换为嵌套散列 [英] Converting a hash into a nested hash

问题描述

这个问题与这个问题相反。

给定一个散列，每个键都有一个数组，例如

Given a hash that has an array for each key like

{
    [:a, :b, :c] => 1,
    [:a, :b, :d] => 2,
    [:a, :e] => 3,
    [:f] => 4,
}

将其转换为嵌套哈希的最佳方式是

what is the best way to convert it into a nested hash like

{
    :a => {
       :b => {:c => 1, :d => 2},
       :e => 3,
    },
    :f => 4,
}

推荐答案

，一个递归的留给练习读者：

Here's an iterative solution, a recursive one is left as an exercise to the reader:

def convert(h={})
  ret = {}
  h.each do |k,v|
    node = ret
    k[0..-2].each {|x| node[x]||={}; node=node[x]}
    node[k[-1]] = v
  end
  ret
end

convert(your_hash) # => {:f=>4, :a=>{:b=>{:c=>1, :d=>2}, :e=>3}}

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