How do I loop over a hash of hashes?

Question

I have this hash:

 h
 => {"67676.mpa"=>{:link=>"pool/sdafdsaff", :size=>4556}} 

>  h.each do |key, value|
>     puts key
>   puts value
>   end
67676.mpa
linkpool/sdafdsaffsize4556

How do I access the separate values in the value hash on the loop?

the appcoach shingara used worked out great....i must of drawn a blank...the answer was right in front of me...i had to do an inner loop — Matt Elhotiby, Feb 14 '12 at 16:04
it's well known the output of puts on a hash is pretty useless, did you try "puts hash.inspect"? — tokland, Feb 14 '12 at 16:06

score 171 · Accepted Answer · edited Dec 18 '13 at 07:53

171

Value is a Hash to so you need iterate on it or you can get only values:-

h.each do |key, value|
  puts key
  value.each do |k,v|
    puts k
    puts v
  end
end

or

h.each do |key, value|
  puts key
  value.values.each do |v|
    puts v
  end
end

edited Dec 18 '13 at 07:53

Gaurav Sharma

477
9
24

answered Feb 14 '12 at 15:49

shingara

46,608
11
99
105

here what if key isn't used anywhere ? . do we need to put a `?` in place of key ? ex : `|?, array|` is this valid syntax for `Ruby` ? – huzefa biyawarwala Mar 16 '16 at 11:30
@huzefabiyawarwala if the key isn't used in the iteration you should prefix it with an underscore like so `|_key, value|` – Severin Feb 21 '17 at 09:54

score 18 · Answer 2 · answered Apr 12 '13 at 16:49

18

You'll want to recurse through the hash, here's a recursive method:

def ihash(h)
  h.each_pair do |k,v|
    if v.is_a?(Hash)
      puts "key: #{k} recursing..."
      ihash(v)
    else
      # MODIFY HERE! Look for what you want to find in the hash here
      puts "key: #{k} value: #{v}"
    end
  end
end

You can Then take any hash and pass it in:

h = {
    "x" => "a",
    "y" => {
        "y1" => {
            "y2" => "final"
        },
        "yy1" => "hello"
    }
}
ihash(h)

answered Apr 12 '13 at 16:49

Travis Reeder

38,611
12
87
87

here what if key isn't used anywhere ? . do we need to put a `?` in place of key ? ex : `|?, array|` is this valid syntax ? – huzefa biyawarwala Mar 16 '16 at 11:39
Keep it, just don't use it. question mark is not valid. – Travis Reeder Mar 16 '16 at 17:22

score 9 · Answer 3 · answered Jul 02 '14 at 04:06

9

I little improved Travis's answer, how about this gist:

https://gist.github.com/kjakub/be17d9439359d14e6f86

class Hash

  def nested_each_pair
    self.each_pair do |k,v|
      if v.is_a?(Hash)
        v.nested_each_pair {|k,v| yield k,v}
      else
        yield(k,v)
      end
    end
  end

end

{"root"=>{:a=>"tom", :b=>{:c => 1, :x => 2}}}.nested_each_pair{|k,v|
  puts k
  puts v
}

answered Jul 02 '14 at 04:06

Jakub Kuchar

1,665
2
23
39

@Travis R improved answer – Jakub Kuchar Jul 02 '14 at 04:21

Jeremy Lynch · Answer 4 · 2013-08-12T12:24:59.510

5

The simplest way to separate out all three values in this case would be as follows:

h.each do |key, value|
  puts key
  puts value[:link]
  puts value[:size]
end

edited Aug 12 '13 at 12:24

answered Aug 12 '13 at 00:10

Jeremy Lynch

6,780
3
52
63

score 2 · Answer 5 · answered Feb 14 '12 at 15:47

You can access the values of a hash directly by calling hash.values. In this case you could do something like

> h = {"67676.mpa"=>{:link=>"pool/sdafdsaff", :size=>4556}}
> h.values.each do |key, value|
>   puts "#{key} #{value}"
> end

link pool/sdafsaff
size 4556

How do I loop over a hash of hashes?

5 Answers5

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