GOOGLE SPREADSHEET SCRIPT TO CHECK THE DUPLICATE ENTRIES IN THE SHEET

Note:

I have updated the script so that you can easily change the range, so now it can work to check duplicates in any column or any row or any range. And it is much more optimized:

http://igoogledrive.blogspot.com/2013/07/how-to-check-duplicates-in-any-range.html

Copy the following script in the "Script editor":

//=====================


function onOpen() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet();
  var entries = [{name : "Check Duplicates",functionName : "checkDuplicates"}];
  sheet.addMenu("Scripts", entries);
};

function checkDuplicates() {
  var sheet = SpreadsheetApp.getActiveSheet();
  var dataRange = sheet.getDataRange();
  var data = dataRange.getValues();
  var numRows = data.length;
  var numColumns = data[0].length;

  var formats = [];
  var values = [];
  for (var i = 0; i < numRows; i++) {
    formats[i] = [];
    for (var j = 0; j < numColumns; j++) {
      formats[i][j] = 'WHITE';
      if (data[i][j] != '') {
        values.push([data[i][j], i, j]);
      }
    }
  }
  var numValues = values.length;
 
  for (var k = 0 ; k < numValues - 1; k++) {
    if (formats[values[k][1]][values[k][2]] == 'WHITE') {
      for (var l = k + 1; l < numValues; l++) {
        if (values[k][0] == values[l][0]) {
          formats[values[k][1]][values[k][2]] = 'RED';
          formats[values[l][1]][values[l][2]] = 'RED';
        }
      }
    }
  }
   
  dataRange.setBackgroundColors(formats);
}


//=====================

And If you are not much familiar with scripts then check out the following link:

http://igoogledrive.blogspot.in/2012/08/how-to-write-script-in-google.html 

I hope the above solution will help you, and if you need more help then please do comment below on this blog itself, I will try to help you out.

I also take up private or confidential projects:

http://igoogledrive.blogspot.in/p/paid-projects.html

If this blog post was helpful to you, and if you think you want to help me too and make my this blog survive then please donate here: http://igoogledrive.blogspot.com/2012/09/donate.html 

Thanks,

Kishan,

iGoogleDrive