table_data.json

{
  "head": [
    {
      "CoType": "CoType",
      "objects": "objects",
      "objects_avg_quality": "objects_avg_quality"
    }
  ],
  "rows": [
    {
      "CoType": "2D_MUSEUM",
      "objects": 162.0,
      "objects_avg_quality": 0.382777777902874
    },
    {
      "CoType": "3D_S_DEVICE",
      "objects": 17.0,
      "objects_avg_quality": 0.410000006065649
    },
    {
      "CoType": "3D_S_DRESS",
      "objects": 17.0,
      "objects_avg_quality": 0.291764703743598
    },
    {
      "CoType": "3D_S_MUSEUM",
      "objects": 225.0,
      "objects_avg_quality": 0.305511112146907
    },
    {
      "CoType": "OTHER",
      "objects": 28.0,
      "objects_avg_quality": 0.150000005960464
    },
    {
      "CoType": "OTHER_NATURAL_HERITAGE",
      "objects": 165.0,
      "objects_avg_quality": 0.300242426630222
    },
    {
      "CoType": "TEXT_PERIODICAL",
      "objects": 1.0,
      "objects_avg_quality": 0.600000023841858
    },
    {
      "sum_avg": "sum_avg",
      "objects": 615.0,
      "objects_avg_quality": 0.3486137223273674
    }
  ]
}

table_data_transposed.json

{
  "head": {
    "col0": "CoType",
    "col1": "2D_MUSEUM",
    "col2": "3D_S_DEVICE",
    "col3": "3D_S_DRESS",
    "col4": "3D_S_MUSEUM",
    "col5": "OTHER",
    "col6": "OTHER_NATURAL_HERITAGE",
    "col7": "TEXT_PERIODICAL",
    "col8": "sum_avg"
  },
  "rows": [
    {
      "col0": "objects",
      "col1": 162.0,
      "col2": 17.0,
      "col3": 17.0,
      "col4": 225.0,
      "col5": 28.0,
      "col6": 165.0,
      "col7": 1.0,
      "col8": 615.0
    },
    {
      "col0": "objects_avg_quality",
      "col1": 0.382777777902874,
      "col2": 0.410000006065649,
      "col3": 0.291764703743598,
      "col4": 0.305511112146907,
      "col5": 0.150000005960464,
      "col6": 0.300242426630222,
      "col7": 0.600000023841858,
      "col8": 0.3486137223273674
    }
  ]
}

transpose_table.rb

  def transpose(table_data)
    data = []
    data = table_data[:head] + table_data[:rows]

    col = 0
    data_transposed = []
    data.each do |h|
      row = []
      h.each do |k,v|
        row.push(["col#{col}", v])
      end
      data_transposed.push(row)
      col = col + 1
    end

    table_transposed = data_transposed.transpose.map(&:to_h)

    {
      head: table_transposed.shift,
      rows: table_transposed
    }
  end