How do you create a "reverse pivot" in Google Sheets?

Question

I am trying to produce a "reverse pivot" function. I have searched long and hard for such a function, but cannot find one that is already out there.

I have a summary table with anywhere up to 20 columns and hundreds of rows, however I would like to convert it into a flat list so I can import to a database (or even use the flat data to create more pivot tables from!)

So, I have data in this format:

	Customer 1	Customer 2	Customer 3
Product 1	1	2	3
Product 2	4	5	6
Product 3	7	8	9

And need to convert it to this format:

 Customer  |  Product  | Qty
-----------+-----------+----
Customer 1 | Product 1 |   1
Customer 1 | Product 2 |   4
Customer 1 | Product 3 |   7
Customer 2 | Product 1 |   2
Customer 2 | Product 2 |   5
Customer 2 | Product 3 |   8
Customer 3 | Product 1 |   3
Customer 3 | Product 2 |   6
Customer 3 | Product 3 |   9

I have created a function that will read the range from sheet1 and append the re-formatted rows at the bottom of the same sheet, however I am trying to get it working so I can have the function on sheet2 that will read the whole range from sheet1.

No matter what I try, I can't seem to get it to work, and was wondering if anybody could give me any pointers?

Here is what I have so far:

function readRows() {
  var sheet = SpreadsheetApp.getActiveSheet();
  var rows = sheet.getDataRange();
  var numRows = rows.getNumRows();
  var values = rows.getValues();

  heads = values[0]
  
  for (var i = 1; i <= numRows - 1; i++) {
    for (var j = 1; j <= values[0].length - 1; j++) {
       var row = [values[i][0], values[0][j], values[i][j]];
       sheet.appendRow(row)
    }
  }
};

Answer 1

I wrote a simple general custom function, which is 100% reusable you can unpivot / reverse pivot a table of any size.

In your case you could use it like this: =unpivot(A1:D4,1,1,"customer","sales")

So you can use it just like any built-in array function in spreadsheet.

Please see here 2 examples: https://docs.google.com/spreadsheets/d/12TBoX2UI_Yu2MA2ZN3p9f-cZsySE4et1slwpgjZbSzw/edit#gid=422214765

The following is the source:

/**
 * Unpivot a pivot table of any size.
 *
 * @param {A1:D30} data The pivot table.
 * @param {1} fixColumns Number of columns, after which pivoted values begin. Default 1.
 * @param {1} fixRows Number of rows (1 or 2), after which pivoted values begin. Default 1.
 * @param {"city"} titlePivot The title of horizontal pivot values. Default "column".
 * @param {"distance"[,...]} titleValue The title of pivot table values. Default "value".
 * @return The unpivoted table
 * @customfunction
 */
function unpivot(data,fixColumns,fixRows,titlePivot,titleValue) {  
  var fixColumns = fixColumns || 1; // how many columns are fixed
  var fixRows = fixRows || 1; // how many rows are fixed
  var titlePivot = titlePivot || 'column';
  var titleValue = titleValue || 'value';
  var ret=[],i,j,row,uniqueCols=1;

  // we handle only 2 dimension arrays
  if (!Array.isArray(data) || data.length < fixRows || !Array.isArray(data[0]) || data[0].length < fixColumns)
    throw new Error('no data');
  // we handle max 2 fixed rows
  if (fixRows > 2)
    throw new Error('max 2 fixed rows are allowed');

  // fill empty cells in the first row with value set last in previous columns (for 2 fixed rows)
  var tmp = '';
  for (j=0;j<data[0].length;j++)
    if (data[0][j] != '') 
      tmp = data[0][j];
    else
      data[0][j] = tmp;

  // for 2 fixed rows calculate unique column number
  if (fixRows == 2)
  {
    uniqueCols = 0;
    tmp = {};
    for (j=fixColumns;j<data[1].length;j++)
      if (typeof tmp[ data[1][j] ] == 'undefined')
      {
        tmp[ data[1][j] ] = 1;
        uniqueCols++;
      }
  }

  // return first row: fix column titles + pivoted values column title + values column title(s)
  row = [];
    for (j=0;j<fixColumns;j++) row.push(fixRows == 2 ? data[0][j]||data[1][j] : data[0][j]); // for 2 fixed rows we try to find the title in row 1 and row 2
    for (j=3;j<arguments.length;j++) row.push(arguments[j]);
  ret.push(row);

  // processing rows (skipping the fixed columns, then dedicating a new row for each pivoted value)
  for (i=fixRows; i<data.length && data[i].length > 0; i++)
  {
    // skip totally empty or only whitespace containing rows
    if (data[i].join('').replace(/\s+/g,'').length == 0 ) continue;

    // unpivot the row
    row = [];
    for (j=0;j<fixColumns && j<data[i].length;j++)
      row.push(data[i][j]);
    for (j=fixColumns;j<data[i].length;j+=uniqueCols)
      ret.push( 
        row.concat([data[0][j]]) // the first row title value
        .concat(data[i].slice(j,j+uniqueCols)) // pivoted values
      );
  }

  return ret;
}

Answer 2

That is basically array manipulation... below is a code that does what you want and writes back the result below existing data.

You can of course adapt it to write on a new sheet if you prefer.

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);
}

to automatically write the result in a new sheet replace last line of code with these :

  var ns = SpreadsheetApp.getActive().getSheets().length+1
  SpreadsheetApp.getActiveSpreadsheet().insertSheet('New Sheet'+ns,ns).getRange(1,1,output.length,output[0].length).setValues(output);

Answer 3

Using simple, yet powerful loops on V8 engine:

/**
 * Unpivots the given data
 *
 * @return Unpivoted data from array
 * @param {A1:C4} arr 2D Input Array
 * @param {1=} ignoreCols [optional] Number of columns on the left to ignore
 * @customfunction
 */
const unpivot = (arr, ignoreCols = 1) =>
  ((j, out) => {
    while (++j < arr[0].length)
      ((i) => {
        while (++i < arr.length)
          out.push([arr[0][j], ...arr[i].slice(0, ignoreCols), arr[i][j]]);
      })(0);
    return out;
  })(ignoreCols - 1, []);

Usage:

=UNPIVOT(A1:C4)
=UNPIVOT(A1:F4,3)//3 static cols on left
={{"Customer","Products","Qty"};UNPIVOT(A1:D4)}//add headers

Live demo:

/*<ignore>*/console.config({maximize:true,timeStamps:false,autoScroll:false});/*</ignore>*/
const arr = [
  ['          ', ' Customer 1 ', ' Customer 2 ', ' Customer 3'],
  ['Product 1 ', '          1 ', '          2 ', '          3'],
  ['Product 2 ', '          4 ', '          5 ', '          6'],
  ['Product 3 ', '          7 ', '          8 ', '          9'],
];
console.log("Input table")
console.table(arr)
/**
 * Unpivots the given data
 *
 * @return Unpivoted data from array
 * @param {A1:C4} arr 2D Input Array
 * @param {1=} ignoreCols [optional] Number of columns on the left to ignore
 * @customfunction
 */
const unpivot = (arr, ignoreCols = 1) =>
  ((j, out) => {
    while (++j < arr[0].length)
      ((i) => {
        while (++i < arr.length)
          out.push([arr[0][j], ...arr[i].slice(0, ignoreCols), arr[i][j]]);
      })(0);
    return out;
  })(ignoreCols - 1, []);
console.log("Output table")
console.table(unpivot(arr));
console.log("Output table with 2 static columns")
console.table(unpivot(arr,2));

<!-- https://meta.stackoverflow.com/a/375985/ -->    <script src="https://gh-canon.github.io/stack-snippet-console/console.min.js"></script>

---

All functions below are provided for historical reasons, but are deprecated

Using ES6-Array.flatMap on V8 engine:

/**
 * Unpivots the given data
 *
 * @return Unpivoted data from array
 * @param {object[][]} arr 2D Input Array
 * @param {object[][]=} headers [optional] Custom headers for output
 * @customfunction
 * @deprecated
 */
function unpivotold(arr, headers) {
  const custHeader = arr.shift();
  custHeader.shift();
  const out = arr.flatMap(([prod, ...qty]) =>
    qty.map((num, i) => [custHeader[i], prod, num])
  );
  if (headers) out.unshift(headers[0]);
  return out;
}

Usage:

=UNPIVOTOLD(A1:F4,{A1,"Month","Sales"})

---

Array manipulation using array.reduce and array.splice - minimalistic approach:

/**
 * Unpivots the given data
 *
 * @deprecated
 * @return Unpivoted data from array
 * @param {A1:F4} arr 2D Input Array
 * @param {3} numCol Number of static columns on the left
 * @param {A1:C1} headers [optional] Custom headers for output
 * @customfunction
 */
function unpivotod(arr, numCol, headers) {
  var out = arr.reduce(function(acc, row) {
    var left = row.splice(0, numCol); //static columns on left
    row.forEach(function(col, i) {
      acc.push(left.concat([acc[0][i + numCol], col])); //concat left and unpivoted right and push as new array to accumulator
    });
    return acc;
  }, arr.splice(0, 1));//headers in arr as initial value
  headers ? out.splice(0, 1, headers[0]) : null; //use custom headers, if present.
  return out;
}

Usage:

=UNPIVOTOD(A1:F4,1,{A1,"Month","Sales"})//Outputs 1 static and 2 unpivoted columns from 1 static and 4+ pivoted columns 

Answer 4

Use FLATTEN. It converts any array into single column.

Here's the formula for unpivot:

=ARRAYFORMULA(SPLIT(FLATTEN(A2:A12&"?"&B1:F1&"?"&B2:F12),"?"))

FLATTEN creates 1-column array of Item1?Date1?67455 strings, which we then split.

Please copy the sample file to try.

Shorter:

=index(SPLIT(FLATTEN(A2:A12&"?"&B1:F1&"?"&B2:F12),"?"))

---

Please also see this solution.

It uses INDIRECT and settings, so the formula looks like a more general solution:

Answer 5

I didn't think you had enough array formula answers so here's another one.

Test Data (Sheet 1)

Formula for customer

=ArrayFormula(hlookup(int((row(indirect("1:"&Tuples))-1)/Rows)+2,{COLUMN(Sheet1!$1:$1);Sheet1!$1:$1},2))

(uses a bit of math to make it repeat and hlookup to find correct column in column headers)

Formula for product

=ArrayFormula(vlookup(mod(row(indirect("1:"&Tuples))-1,Rows)+2,{row(Sheet1!$A:$A),Sheet1!$A:$A},2))

(similar approach using mod and vlookup to find correct row in row headers)

Formula for quantity

=ArrayFormula(vlookup(mod(row(indirect("1:"&Tuples))-1,Rows)+2,{row(Sheet1!$A:$A),Sheet1!$A:$Z},int((row(indirect("1:"&Tuples))-1)/Rows)+3))

(extension of above approach to find both row and column in 2d array)

Then combining these three formulas into a query to filter out any blank values for quantity

=ArrayFormula(query(
   {hlookup(int((row(indirect("1:"&Tuples))-1)/Rows)+2, {COLUMN(Sheet1!$1:$1);Sheet1!$1:$1},2),
    vlookup(mod(row(indirect("1:"&Tuples))-1,Rows)+2,{row(Sheet1!$A:$A),Sheet1!$A:$A},2),
    vlookup(mod(row(indirect("1:"&Tuples))-1,Rows)+2,{row(Sheet1!$A:$A),Sheet1!$A:$Z},int((row(indirect("1:"&Tuples))-1)/Rows)+3)},
"select * where Col3 is not null"))

Note

The named ranges Rows and Cols are obtained from the first column and row of the data using counta and Tuples is their product. The separate formulas

=counta(Sheet1!A:A)

=counta(Sheet1!1:1)

and

=counta(Sheet1!A:A)*counta(Sheet1!1:1)

could be included in the main formula if required with some loss of readability.

---

For reference, here is the 'standard' split/join solution (with 50K data limit) adapted for the present situation:

=ArrayFormula(split(transpose(split(textjoin("?",true,transpose(if(Sheet1!B2:Z="","",Sheet1!B1:1&"?"&Sheet1!A2:A&"?"&Sheet1!B2:Z))),"?")),"?"))

This is also fairly slow (processing 2401 array elements). If you restrict the computation to the actual dimensions of the data, it is much faster for small datasets:

=ArrayFormula(split(transpose(split(textjoin("?",true,transpose(if(Sheet1!B2:index(Sheet1!B2:Z,counta(Sheet1!A:A),counta(Sheet1!1:1))="","",Sheet1!B1:index(Sheet1!B1:1,counta(Sheet1!1:1))&"?"&Sheet1!A2:index(Sheet1!A2:A,counta(Sheet1!A:A))&"?"&Sheet1!B2:index(Sheet1!B2:Z,counta(Sheet1!A:A),counta(Sheet1!1:1))))),"?")),"?"))

Answer 6

=ARRAYFORMULA({"Customer", "Product", "Qty"; 
 QUERY(TRIM(SPLIT(TRANSPOSE(SPLIT(TRANSPOSE(QUERY(TRANSPOSE(QUERY(TRANSPOSE(
 IF(B2:Z<>"", B1:1&"?"&A2:A&"?"&B2:Z&"?", )), , 999^99)), , 999^99)), "?")), "?")), 
 "where Col1<>'' order by Col1")})

Answer 7

Here another alternative:

=arrayformula
(
   { "PRODUCT","CUSTOMER","QTY";
     split 
     ( transpose ( split 
                   ( textjoin("?" ,false,filter(Sheet2!A2:A,Sheet2!A2:A<>"") & "?" &
                              filter(Sheet2!B1:1,Sheet2!B1:1<>""))
                     ,"?",true,false)),"?",true,false
     ),
     transpose ( split ( textjoin ( "?", false, transpose ( filter 
     ( 
       indirect( "Sheet2!B2:"  & MID(address(1,COUNTA( Sheet2!B1:1)+1), 2,
                                     FIND("$",address(1,COUNTA( Sheet2!B1:1)+1),2)-2)
               )   
       , Sheet2!A2:A<>""
       ))),"?",true,false)
     )
   }
 )

Explanation:

1. "PRODUCT","CUSTOMER","QTY"
   -- Use for giving title

2. split 
   ( transpose ( split 
               ( textjoin("?" ,false,filter(Sheet2!A2:A,Sheet2!A2:A<>"") & "?" &
                          filter(Sheet2!B1:1,Sheet2!B1:1<>""))
               ,"?",true,false)),"?",true,false
   )
   -- Use for distributing Row1 and ColumnA, to be Product and Customer Columns

3. transpose ( split ( textjoin ( "?", false, transpose ( filter 
   ( 
     indirect( "Sheet2!B2:"  & MID(address(1,COUNTA( Sheet2!B1:1)+1), 2,
                                 FIND("$",address(1,COUNTA( Sheet2!B1:1)+1),2)-2)
             )   
     , Sheet2!A2:A<>""
     ))),"?",true,false)
   )
   --use to distributed data qty to Qty Column

Sheet2 Pict:

Result Sheet Pict:

Answer 8

Input Sheet

This function will handle many customers and many products and it will sum the quantities of multiple customer/product entries and summarize it into one simple table.

The Code:

function rPVT() {
  var ss=SpreadsheetApp.getActive();
  var sh=ss.getSheetByName('Sheet1');
  var osh=ss.getSheetByName('Sheet2');
  osh.clearContents();
  var vA=sh.getDataRange().getValues();
  var itoh={};
  var pObj={};
  vA[0].forEach(function(h,i){if(h){itoh[i]=h;}});
  for(var i=1;i<vA.length;i++) {
    for(var j=1;j<vA[i].length;j++) {
      if(!pObj.hasOwnProperty(itoh[j])){pObj[itoh[j]]={};}
      if(!pObj[itoh[j]].hasOwnProperty(vA[i][0])){pObj[itoh[j]][vA[i][0]]=vA[i][j];}else{pObj[itoh[j]][vA[i][0]]+=(vA[i][j]);}
    }
  }
  var oA=[['Customer','Product','Quantity']];  
  Object.keys(pObj).forEach(function(ik){Object.keys(pObj[ik]).forEach(function(jk){oA.push([ik,jk,pObj[ik][jk]]);});});
  osh.getRange(1,1,oA.length,oA[0].length).setValues(oA);
}

Output Sheet:

The following function reads Sheet2 which is the output of the above function and returns it to the original format.

function PVT() {
  var ss=SpreadsheetApp.getActive();
  var sh2=ss.getSheetByName('Sheet2');
  var sh3=ss.getSheetByName('Sheet3');
  sh3.clearContents();
  var vA=sh2.getRange(2,1,sh2.getLastRow()-1,sh2.getLastColumn()).getValues();
  pObj={};
  vA.forEach(function(r,i){if(!pObj.hasOwnProperty(r[1])){pObj[r[1]]={};}if(!pObj[r[1]].hasOwnProperty(r[0])){pObj[r[1]][r[0]]=r[2];}else{pObj[r[1]][r[0]]+=r[2];}});
  var oA=[];
  var ikeys=Object.keys(pObj);
  var jkeys=Object.keys(pObj[ikeys[0]]);
  var hkeys=jkeys.slice();
  hkeys.unshift(''); 
  oA.push(hkeys);
  ikeys.forEach(function(ik,i){var row=[];row.push(ik);jkeys.forEach(function(jk,j){row.push(pObj[ik][jk]);});oA.push(row);});
  sh3.getRange(1,1,oA.length,oA[0].length).setValues(oA);
}

Answer 9

If your data has a single unique key column, this spreadsheet may have what you need.

Your unpivot sheet will contain:

• The key column =OFFSET(data!$A$1,INT((ROW()-2)/5)+1,0)
• The column header column =OFFSET(data!$A$1,0,IF(MOD(ROW()-1,5)=0,5,MOD(ROW()-1,5)))
• The cell value column =INDEX(data!$A$1:$F$100,MATCH(A2,data!$A$1:$A$100,FALSE),MATCH(B2,data!$A$1:$F$1,FALSE))

where 5 is the number of columns to unpivot.

---

I did not make the spreadsheet. I happened across it in the same search that led me to this question.