Method: Marty::DataExporter.hash_array_merge

Defined in:
lib/marty/data_exporter.rb

.hash_array_merge(hl, transpose) ⇒ Object 



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# File 'lib/marty/data_exporter.rb', line 7

def self.hash_array_merge(hl, transpose)
  # given a list of hashes hl, generates a merged hash.  The
  # resulting hash contains a superset of all the hash keys.  The
  # values are corresponding values from each hash in hl.
  # e.g. the following
  #
  # [{"a"=>1, "b"=>2}, {"a"=>11, "c"=>33}, {"a"=>1111, "b"=>222, "c"=>333}]
  #
  # maps to ...
  #
  # [["a", "b", "c"], [1, 2, nil], [11, nil, 33], [1111, 222, 333]]

  keys = hash_array_keys(hl)

  return keys.each_with_object({}) do |k, rh|
      rh[k] = hl.map { |h| h[k] }
  end if transpose

  [keys.to_a] + hl.map { |h| keys.map { |k| h[k] } }
end