Matrix to Column using Google Script

Question

Completely new to coding, I need to un-pivot rows into a column in Google script as a function (not a formula)

Depending on the project their can be 100 columns and where I need to start the un-pivot from can vary so in a different project Column "X" instead of Column "C" in the below example

I have search for hours and found nothing that works as I need.

Edit: better example

Data looks like

A1  A2  A3  A4  A5  A6  A7
a1  b1  c1  d1  e1  f1  g1
a2  b2  c2  d2  e2  f2  g2
a3  b3  c3  d3  e3  f3  g3
a4  b4  c4  d4  e4  f4  g4

Need

A1  A2  A3  New New1
a1  b1  c1  A4  d1
a1  b1  c1  A5  e1
a1  b1  c1  A6  f1
a1  b1  c1  A7  g1
a2  b2  c2  A4  d2
a2  b2  c2  A5  e2
a2  b2  c2  A6  f2
a2  b2  c2  A7  g2
a3  b3  c3  A4  d3
a3  b3  c3  A5  e3
a3  b3  c3  A6  f3
a3  b3  c3  A7  g3
a4  b4  c4  A4  d4
a4  b4  c4  A5  e4
a4  b4  c4  A6  f4 

I found this and it seems promising: How do you create a "reverse pivot" in Google Sheets?

Thanks in advance for assistance

function transformData(){
  var sheet = SpreadsheetApp.getActiveSheet();
  var data = sheet.getDataRange().getValues();//read whole sheet
  var output = [];
  var headers = data.shift();// get headers
  var empty = headers.shift();//remove empty cell on the left
  var products = [];
    for(var d in data){
      var p = data[d].shift();//get product names in first column of each row
      products.push(p);//store
    }
  Logger.log('headers = '+headers);
  Logger.log('products = '+products);
  Logger.log('data only ='+data);
  for(var h in headers){
    for(var p in products){  // iterate with 2 loops (headers and products)
      var row = [];
      row.push(headers[h]);
      row.push(products[p]);
      row.push(data[p][h])
      output.push(row);//collect data in separate rows in output array
    }
  }
   Logger.log('output array = '+output);

  sheet.getRange(sheet.getLastRow()+1,1,output.length,output[0].length)
   .setValues(output);
  }

Answer 1

How about the following sample script?

Sample script :

function transformData(){
  var sheet = SpreadsheetApp.getActiveSheet();
  var data = sheet.getDataRange().getValues();
  var header = data[0].slice(3, 5);
  var newHeader = [data[0][0], data[0][1], "New", "New1"];
  data.shift();
  var output = [];
  output.push(newHeader);
  for(var i in data) {
    for (var j=0; j<newHeader.length-2; j++) {
      var temp = [];
      temp.push(data[i][0], data[i][1], header[j], data[i][j + 3]);
      output.push(temp);
    }
  }
  sheet.getRange(sheet.getLastRow()+1,1,output.length,output[0].length).setValues(output);
}

Result :

Note :

• If you want to change the header, please modify var newHeader = [data[0][0], data[0][1], "New", "New1"].
• This is a simple sample script. So please modify this for your environment.

If I misunderstand your question, please tell me. I would like to modify.

Edit :

Sample script :

function transformData(){
  var sheet = SpreadsheetApp.getActiveSheet();
  var data = sheet.getDataRange().getValues();
  var header = data[0].slice(-4);
  var newHeader = [data[0][0], data[0][1], data[0][2], "New", "New1"];
  data.shift();
  var output = [];
  output.push(newHeader);
  for(var i in data) {
    for (var j=0; j<4; j++) {
      var temp = [];
      temp.push(data[i][0], data[i][1], data[i][2], header[j], data[i][j + 3]);
      output.push(temp);
    }
  }
  sheet.getRange(sheet.getLastRow()+1,1,output.length,output[0].length).setValues(output);
}

Result :