CODEWITHSUNDEEP
rubyarrayshash
Ben
Ben

Reputation: 759

merging arrays of hashes

I have two arrays, each holding arrays with attribute hashes. 

Array1 => [[{attribute_1 = A}, {attribute_2 = B}], [{attribute_1 = A}, {attribute_4 = B}]]
Array2 => [{attribute_3 = C}, {attribute_2 = D}], [{attribute_3 = C, attribute_4 = D}]]

Each array in the array is holding attribute hashes for an object. In the above example, there are two objects that I'm working with. There are two attributes in each array for each of the two objects.

How do I merge the two arrays? I am trying to get a single array of 'object' arrays (there is no way to get a single array from the start because I have to make two different API calls to get these attributes).

DesiredArray => [[{attribute_1 = A, attribute_2 = B, attribute_3 = C, attribute_4 = D}],
                 [{attribute_1 = A, attribute_2 = B, attribute_3 = C, attribute_4 = D}]]

I've tried a couple things, including the iteration methods and the merge method, but I've been unable to get the array I need.

Upvotes: 1

Views: 2383

Answers (2)

Wayne Conrad
Wayne Conrad

Reputation: 107959

You seem to have parallel arrays of hashes. We can use zip to turn the parallel arrays into a single array of arrays of hashes. We can then map each array of hashes into a single hash using inject and merge:

#!/usr/bin/ruby1.8

require 'pp'

array1 = [{:attribute_1 => :A, :attribute_2 => :B}, {:attribute_1 => :A, :attribute_4 => :B}]
array2 = [{:attribute_3 => :C, :attribute_2 => :D}, {:attribute_3 => :C, :attribute_4 => :D}]

pp array1.zip(array2).collect { |array| array.inject(&:merge) }
# => [{:attribute_2=>:D, :attribute_1=>:A, :attribute_3=>:C},
# =>  {:attribute_4=>:D, :attribute_1=>:A, :attribute_3=>:C}]

Upvotes: 5

nas
nas

Reputation: 3696

I don't think my answer is valid anymore, since the question has been edited later.

Here, first I am fixing your array and hash notation in your question.

Array1 = [{'attribute_1' => 'A', 'attribute_2' => 'B'}, {'attribute_1' => 'A', 'attribute_2' => 'B'}]
#=> [{"attribute_1"=>"A", "attribute_2"=>"B"}, {"attribute_1"=>"A", "attribute_2"=>"B"}]
Array2 = [{'attribute_3' => 'C', 'attribute_2' => 'D'}, {'attribute_3' => 'C', 'attribute_4' => 'D'}]
#=> [{"attribute_2"=>"D", "attribute_3"=>"C"}, {"attribute_3"=>"C", "attribute_4"=>"D"}]

You can simply concatenate the two arrays to get your desired array like so:

DesiredArray = Array1+Array2
# => [{"attribute_1"=>"A", "attribute_2"=>"B"}, {"attribute_1"=>"A", "attribute_2"=>"B", {"attribute_2"=>"D", "attribute_3"=>"C"}, {"attribute_3"=>"C", "attribute_4"=>"D"}]

Upvotes: 1

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