From: Stefan Rusterholz <apeiros@...>
Date: 2009-04-20T20:33:14+09:00
Subject: Re: Hash merge question

A little bit simpler:

result = {}
(h1.keys | h2.keys).each { |key| result[key] = [(h1[key] || []), 
(h2[key] || []) }

No need to abuse inject.

Regards
Stefan

Florian Kaufmann wrote:
> #!/usr/bin/ruby
> h1 = {
>       :a1 => [:y1, :y2, :y3],
>       :a2 => [:y4, :y5, :y6]
>      }
> h2 = {
>       :a2 => [:z1, :z2, :z3],
>       :a3 => [:z4, :z5, :z6]
>      }
> h = {}
> (h1.keys + h2.keys).each {|k| h[k] = [[],[]] }
> h = h1.to_a.inject(h) { |i,kv| i[kv[0]][0] = kv[1]; i }
> h = h2.to_a.inject(h) { |i,kv| i[kv[0]][1] = kv[1]; i }
> p h
> 
> gives
> 
> {:a2=>[[:y4, :y5, :y6], [:z1, :z2, :z3]], :a1=>[[:y1, :y2, :y3],
> []], :a3=>[[], [:z4, :z5, :z6]]}
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