From: Sandor Szuecs <sandor.szuecs@...>
Date: 2010-10-24T18:27:42+09:00
Subject: Re: Convert Array to nested Hash


On Oct 24, 2010, at 7:25 AM, Zhi-Qiang Lei wrote:

> Dear All,
> 
> I'm seeking a method to convert an array like:
> 
> [
> 	["A", "a", 1]
> 	["A", "b", 2]
> 	["B", "a", 1]
> 
> ]
> 
> into a hash as follow:
> {
> 	{"A" => {"a" => 1, "b" => 2}},
> 	{"B" => {"a" => 1}}
> }
> 
> Do you have any idea on this? Thanks in advance.

I don't think that you really want to add 3 layers of dictionary.
If you really want this, then you think about your abstractions to 
get a simpler solution.

  a = [
    ["A", "a", 1],
    ["A", "b", 2],
    ["B", "a", 1]
  ]
  
def a_to_h(a)
  h={}
  a.map do |nested|
    key = nested.shift
    h[key] ||= {}
    h[key].merge!({ nested.shift => nested.shift })
  end  
  h
end

irb:0> a_to_h(a)
=> {"A"=>{"a"=>1, "b"=>2}, "B"=>{"a"=>1}}


All the best, Sandor Szücs
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