Put every Hash Element inside of an Array Ruby

Question

Let's say I have a Hash like this:

my_hash = {"a"=>{"a1"=>"b1"}, "b"=>"b", "c"=>{"c1"=>{"c2"=>"c3"}}}

And I want to convert every element inside the hash that is also a hash to be placed inside of an Array.

For example, I want the finished Hash to look like this:

{"a"=>[{"a1"=>"b1"}], "b"=>"b", "c"=>[{"c1"=>[{"c2"=>"c3"}]}]}

Here is what I've tried so far, but I need it to work recursively and I'm not quite sure how to make that work:

my_hash.each do |k,v|
  if v.class == Hash
    my_hash[k] = [] << v
  end
end
 => {"a"=>[{"a1"=>"b1"}], "b"=>"b", "c"=>[{"c1"=>{"c2"=>"c3"}}]}

@sergiotulentsev, now both answers are deleted. Both should be turned into community wiki answers. — the Tin Man
– the Tin Man, Commented Dec 23, 2015 at 17:50
@theTinMan: Hm, I see one still standing. No need to have them both. — Sergio Tulentsev
– Sergio Tulentsev, Commented Dec 23, 2015 at 17:52
@SergioTulentsev, Yes, the other was undeleted right after the comment-exchange. — the Tin Man
– the Tin Man, Commented Dec 23, 2015 at 17:55
Would it not be more convenient if all the hash values were arrays, as you could always check if h[k].is_a? Hash. — Cary Swoveland
– Cary Swoveland, Commented Dec 23, 2015 at 19:49
Why the down votes? I clearly state my need and my attempted solution? — Trinculo
– Trinculo, Commented Jan 12, 2016 at 15:48

2 revs · Accepted Answer · 2015-12-23 19:21:09Z

4

You need to wrap your code into a method and call it recursively.

my_hash = {"a"=>{"a1"=>"b1"}, "b"=>"b", "c"=>{"c1"=>{"c2"=>"c3"}}}

def process(hash)
    hash.each do |k,v|
      if v.class == Hash
        hash[k] = [] << process(v)
      end
    end
end

p process(my_hash)
#=> {"a"=>[{"a1"=>"b1"}], "b"=>"b", "c"=>[{"c1"=>[{"c2"=>"c3"}]}]}

edited Dec 23, 2015 at 19:21

community wiki

2 revs
Wand Maker

Sign up to request clarification or add additional context in comments.

2 Comments

Cary Swoveland Over a year ago

Good one, Wand. You could alternatively write hash[k] = [process(v)].

Wand Maker Over a year ago

@CarySwoveland I did not mess with the original code much, its pretty much what OP had. Feel free to update it as its community wiki

stefkin · Accepted Answer · 2015-12-23 23:40:32Z

2

Recurring proc is another way around:

h = {"a"=>{"a1"=>"b1"}, "b"=>"b", "c"=>{"c1"=>{"c2"=>"c3"}}}
h.map(&(p = proc{|k,v| {k => v.is_a?(Hash) ? [p[*v]] : v}}))
 .reduce({}, &:merge)
# => {"a"=>[{"a1"=>"b1"}], "b"=>"b", "c"=>[{"c1"=>[{"c2"=>"c3"}]}]}

It can be done with single reduce, but that way things get even more obfuscated.

edited Dec 23, 2015 at 23:40

answered Dec 23, 2015 at 23:35

stefkin

6797 silver badges19 bronze badges

Collectives™ on Stack Overflow

Put every Hash Element inside of an Array Ruby

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related