How to make first array the header and remaining arrays rows of objects

Question

I am new to coding and trying to get this problem right. I tried calling the index of the arrays but it prints out columns. Out dev environment is REPL.it, the virtual machine uses node v10.16.0 and help would be greatly appreciate

Input

tableData = [
    ["first_name", "last_name", "city", "state"],
    ["Elisabeth", "Gardenar", "Toledo", "OH"],
    ["Jamaal", "Du", "Sylvania", "OH"],
    ["Kathlyn", "Lavoie", "Maumee", "OH"]
]

Desired Output

output = [
    { first_name : "Elisabeth", last_name : "Gardenar", city: "Toledo", state : "OH" },
    { first_name : "Jamaal", last_name : "Du", city: "Sylvania", state : "OH" },
    { first_name : "Kathlyn", last_name : "Lavoie", city: "Maumee", state : "OH" }
]

What I have tried so far is this:

function convertTable(){
    var p=console.log;
    const [header,...rows] = tableData;
    var tableObj = new Object;
    var intermediateVal = [];
    var finalArr = [];
    for(var vals=0;vals<rows.length;vals++){
        var row = rows[vals]
        for (var key=0,val=0;key<header.length;key++,val++){
            tableObj[header[key]]=row[val]
        }
    p(tableObj)
  }
} 
convertTable(tableData)

Barmar · Accepted Answer · 2019-10-17 00:39:37Z

6

You're pretty close, but you need to create a new object for each row of the result, and then push that object onto the finalArr array.

There's also no need for both key and val variables, since they're always the same.

tableData = [
  ["first_name", "last_name", "city", "state"],
  ["Elisabeth", "Gardenar", "Toledo", "OH"],
  ["Jamaal", "Du", "Sylvania", "OH"],
  ["Kathlyn", "Lavoie", "Maumee", "OH"]
];

function convertTable() {
  var p = console.log;
  const [header, ...rows] = tableData;
  var finalArr = [];
  for (var vals = 0; vals < rows.length; vals++) {
    var row = rows[vals]
    var tableObj = {};
    for (var key = 0; key < header.length; key++) {
      tableObj[header[key]] = row[key]
    }
    finalArr.push(tableObj);
  }
  p(finalArr)

}
convertTable(tableData)

answered Oct 17, 2019 at 0:39

Barmar

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Comments

Nick · Accepted Answer · 2019-10-17 00:43:14Z

4

Here is a potential solution that uses array reduce.

const tableData = [
  ["first_name", "last_name", "city", "state"],
  ["Elisabeth", "Gardenar", "Toledo", "OH"],
  ["Jamaal", "Du", "Sylvania", "OH"],
  ["Kathlyn", "Lavoie", "Maumee", "OH"]
];

const keys = tableData.shift();

const formatted = tableData.reduce((agg, arr) => {
  agg.push(arr.reduce((obj, item, index) => {
    obj[keys[index]] = item;
    return obj;
  }, {}));
  return agg;
}, [])

console.log(formatted);

answered Oct 17, 2019 at 0:43

Nick

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1 Comment

DragoomDoc99 Over a year ago

TL;DR : Thank you, this is great work. Acutal Comment: NICK!!!!!!! that is freaking amazing. I just find it hard to follow it. I am very new to programming. If my teacher compares my code to your code, they will know i cheated on the assignment. I tried Array.shift() method on the rows. It did not occur to me to use it for the header. I was upset, "why can't i get the shift() to loop in the loop!!" Because it didn't make sense. However you are amazing.

Juan · Accepted Answer · 2019-10-17 00:42:20Z

0

You can also leverage the reduce method which is included in arrays.

tableData = [
    ["Elisabeth", "Gardenar", "Toledo", "OH"],
    ["Jamaal", "Du", "Sylvania", "OH"],
    ["Kathlyn", "Lavoie", "Maumee", "OH"]
];

const obj = tableData.reduce((acc, cv, index) => {
        acc.push({
            first_name: cv[0],
            last_name: cv[1],
            city: cv[2],
            state: cv[3]
        });
        return acc
},[]);

console.log(obj); 
// [ { first_name: 'Elisabeth',
//    last_name: 'Gardenar',
//    city: 'Toledo',
//    state: 'OH' },
//  { first_name: 'Jamaal',
//    last_name: 'Du',
//    city: 'Sylvania',
//    state: 'OH' },
//  { first_name: 'Kathlyn',
//   last_name: 'Lavoie',
//    city: 'Maumee',
//   state: 'OH' } ]

answered Oct 17, 2019 at 0:42

Juan

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1 Comment

DragoomDoc99 Over a year ago

Thank you for your comment, however the Object Keys must be dynamic and not static. Otherwise I would use this method.

Luiz Fernando da Silva · Accepted Answer · 2019-10-17 00:48:20Z

0

Another functional approach

const tableData = [
    ["first_name", "last_name", "city", "state"],
    ["Elisabeth", "Gardenar", "Toledo", "OH"],
    ["Jamaal", "Du", "Sylvania", "OH"],
    ["Kathlyn", "Lavoie", "Maumee", "OH"]
]

const [keys, ...values] = tableData

const obtainValues = (line) => {
    const [first_name, last_name, city, state] = line
    return {first_name, last_name, city, state}
}

const output = values.map(obtainValues)

console.log(output)

See demo here

answered Oct 17, 2019 at 0:48

Luiz Fernando da Silva

1,51917 silver badges25 bronze badges

1 Comment

DragoomDoc99 Over a year ago

Thank you for your comment, however the Object Keys must be dynamic and not static. Map kind of confuses me, I can't really get into it.

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