Convert Array of Arrays to Array of Objects-CodePudding

What is the most efficient way to convert the data below in node.js? Any help would be much appreciated. Thanks!

I have some data that looks like this->

inputdata = {
  data1: [5.0, 10.0, 50.0, 100.0, 500.0],
  data2: [5.0, 10.0, 50.0, 100.0, 500.0],
  data3: [5.0, 10.0, 50.0, 100.0, 500.0]
}

and I need to convert it into this->

outputdata = [
{data1: 5.0, data2: 5.0, data3: 5.0},
{data1: 10.0, data2: 10.0, data3: 10.0},
{data1: 50.0, data2: 50.0, data3: 50.0},
{data1: 100.0, data2: 100.0, data3: 100.0},
{data1: 500.0, data2: 500.0, data3: 500.0}
]

Code attempt-->

var inputdata = {
  data1: [5.0, 10.0, 50.0, 100.0, 500.0],
  data2: [5.0, 10.0, 50.0, 100.0, 500.0],
  data3: [5.0, 10.0, 50.0, 100.0, 500.0]
}

var outputdata = [];

Object.keys(inputdata).forEach(key => {
let value = inputdata [key];
    if (key == "data1"){
        for (let i = 0; i < value.length; i  ) {
        outputdata.push({data1: 0, data2: 0, data3: 0})
        }
    }
}

Object.keys(inputdata).forEach(key => {
let value = inputdata [key];
    if (key == "data1"){
    for (let i = 0; i < value.length; i  ) {
      outputdata[i].data1 = value[i];
    }
}
if (key == "data2"){
    for (let i = 0; i < value.length; i  ) {
      outputdata[i].data2 = value[i];
    }
}
if (key == "data3"){
    for (let i = 0; i < value.length; i  ) {
      outputdata[i].data3 = value[i];
    }
}
}

console.log(inputdata);
console.log(outputdata);

CodePudding user response：

You could transpose the data and build new objects from data.

const
    data = { data1: [5, 10, 50, 100, 500], data2: [5, 10, 50, 100, 500], data3: [5, 10, 50, 100, 500] },
    result = Object
        .entries(data)
        .reduce((r, [k, a]) => a.map((v, i) => ({ ...r[i], [k]: v })), []);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

CodePudding user response：

// reducer functions which transposes
// a table into a matrix and vice versa.
function transpose(result, row) {
  return row.reduce((matrix, value, idx) => {

    (matrix[idx] ??= []).push(value);
    return matrix;

  }, result);
}

const inputdata = {
  data1: [5.0, 10.0, 50.0, 100.0, 500.0],
  data2: [5.0, 10.0, 50.0, 100.0, 500.0],
  data3: [5.0, 10.0, 50.0, 100.0, 500.0]
};
console.log(
  Object

    // convert `inputdata` into a table
    // ... an array of row like arrays.
    .values(inputdata)
);
console.log(
  Object

    // - convert `inputdata` into a table
    //   ... an array of row like arrays.
    .values(inputdata)

    // - then transpose the table into a matrix.
    .reduce(transpose, [])
);
console.log(
  Object

    // - convert `inputdata` into a table
    //   ... an array of row like arrays.
    .values(inputdata)

    // - then transpose the table into a matrix.
    .reduce(transpose, [])

    // - then convert/map matrix 
    //   into an array of objects.
    .map(vector =>
      vector.reduce((object, value, idx) =>

        Object.assign(object, {
          [`data${ idx   1 }`]: value,
        }), {}        
      )
    )
);

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