How can I convert tabular row data to column data in javascript

Question

so I need to convert an array that contains tabular row data into column data in a specific format so I can use it to display a chart with Recharts.

My data is in the following format:

rows = [
    ['Year', '2010', '2011', '2012', '2013'], 
    ['wages','2000','2000','2050','2050'], 
    ['purchase cost', '4000', '4300', '4500', '5000']
]

I need the data to be formatted as follows:

columns = [
    {'Year' : '2010', 'wages' : '2000', 'purchase cost' : '4000'}, 
    {'Year' : '2011', 'wages' : '2000', 'purchase cost' : '4300'}, 
    {'Year' : '2012', 'wages' : '2050', 'purchase cost' : '4500'}, 
    {'Year' : '2013', 'wages' : '2050', 'purchase cost' : '5000'}
]

I've gotten close to getting the result I need but can't seem to get it to work, so I would appreciate any help with this!

Ian · Accepted Answer · 2022-01-25 05:35:16Z

1

Keep two principles

The subarrays are all the same length.
The first element of the subarray is the column name.

I implemented it in several steps, you can refer to the following code.

const rows = [
  ['Year', '2010', '2011', '2012', '2013'],
  ['wages', '2000', '2000', '2050', '2050'],
  ['purchase cost', '4000', '4300', '4500', '5000']
];

const property = rows.map(row => row[0]);
const columns = rows.map(row => {
  row.shift();
  return row
});

const data = columns.map((column, i) => {
  return column.map(col => {
    const obj = {};
    obj[property[i]] = col;
    return obj;
  });
});

const result = new Array(columns[0].length);
for (let i = 0; i < result.length; i++) {
  const obj = {};
  for (let j = 0; j < property.length; j++) {
    for (const [key, value] of Object.entries(data[j][i])) {
      obj[key] = value;
    }
  }
  result[i] = obj;
}

console.log(result);

edited Jan 25, 2022 at 5:35

answered Jan 25, 2022 at 5:26

Ian

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2 Comments

Felipe Berger Over a year ago

Thank you so much Ian, that worked perfectly!

Ian Over a year ago

@FelipeBerger Glad to help.

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