CODEWITHSUNDEEP
rubyhashmap
letsc
letsc

Reputation: 2567

Ruby : Extract Key and Value from hash

I have an array of hashes that I'm having trouble with extracting the key and value. The array looks like:

data = [{"key"=>"Name", "value"=>"Jason"}, {"key"=>"Age", "value"=>"21"},
        {"key"=>"last_name", "value"=>"bourne"}]

How can I convert this to the following array of hashes?

[{"Name"=>"Jason"}, {"Age"=>"21"}, {"last_name"=>"bourne"}]

I was able to use detect :

a = d.detect { |x| x["key"] == "Name" }
puts a['value']

to get the value for "name", but would like to know if there is a better way.

Upvotes: 1

Views: 1767

Answers (2)

Cary Swoveland
Cary Swoveland

Reputation: 110675

The calculation should not depend on the keys of the hashes, in case they are changed.

data.map { |h| [h.values].to_h }
  #=> [{"Name"=>"Jason"}, {"Age"=>"21"}, {"last_name"=>"bourne"}]

Upvotes: 1

Aaron Christiansen
Aaron Christiansen

Reputation: 11807

I'd say that the most elegant way to go about this is probably to convert data into a Hash first (assuming there are never any duplicate keys), like so:

data = data.map { |x| [x['key'], x['value']] }.to_h
# => {"Name"=>"Jason", "Age"=>"21", "last_name"=>"bourne"}

The #to_h method expects each element of the array to be an array in the form [key, value], so the #map call processes each element of data to convert it into that form.

Once this has been done, you can simply access keys like any other hash:

data['Name'] # => "Jason"
data['Age'] # => "21"

Upvotes: 1

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