Stack Overflow - Webapplications - Custom data transpose

function transposeColumns(sheetName) {

  if(sheetName == null) sheetName="students";

 // loading sheets to work with
 var ss = SpreadsheetApp.getActiveSpreadsheet();
 var printSheet = ss.getActiveSheet();
 var sheet = ss.getSheetByName(sheetName);

 // we need to know how wide and tall is the sheet
 var lastRow = sheet.getLastRow();
 var lastColumn = sheet.getLastColumn();

 /* storing data - it's basically array of arrays
 [
   [Mentor 1, student 1, student 2, student 3, ...],
   [Mentor 2, student 1, student 2, ...],
   [Mentor 3, student 1, ...]
 ]
 */
 var foundMentors = new Array();

  //set variables to loop through data, scanning begins at cell C2 (coordinates 2,3 - ROW,COLUMN)
  var activeR = 2;
  var activeC = 3;
  var step = 0
  var pushedMentors = 0;
  var studentPushed = 0;

//loop through data on sheet
  for(var r = activeR; r <= lastRow;r++){
    for(var c = activeC; c <= lastColumn;c++){
      step++;
      var mentorName = sheet.getRange(r,c).getValue();
      Logger.log(step+' -- cell:'+r+','+c+' = '+mentorName);
      // if the cell is not empty
      if(mentorName != ''){
        // checking if mentor is unique/already found, id relates to array key
        var mentorId = findMentor(foundMentors, mentorName);
        Logger.log('mentorName: '+mentorName+': has id:'+mentorId);
        // Mentor does not yet exists
        if(mentorId === undefined){
          // adding him to array with current student
          foundMentors[pushedMentors] = new Array(mentorName, sheet.getRange(r,2).getValue());
          pushedMentors++;
        // Mentor exists, push new student name in its array
        } else {
           var newStudent = sheet.getRange(r,2).getValue();
           // checking if the student is unique in Mentors stack/array
           var studentExists = existsInArray(foundMentors[mentorId],newStudent);
           Logger.log('newStudent: '+newStudent+': exists:'+studentExists);
          // student is unique - adding him to Mentors array
           if((studentExists == false) && (newStudent !== undefined)){
             foundMentors[mentorId].push(newStudent);
             studentPushed++;
           }
         }
       }
    }
  }

  // loop for printing results (names) into current sheet
  for(var r = 0; r < foundMentors.length; r++){
    for(var c = 0; c < foundMentors[r].length; c++){
      var studentName = foundMentors[r][c];
      // acutal coordinates of cells are shifted
      printSheet.getRange(r+2, c+1).setValue(studentName);
    }
  }

  // loop for printing out generic student labels
  var printSheetlastColumn = printSheet.getLastColumn();
  for(c = 2; c <= printSheetlastColumn; c++){
     printSheet.getRange(1, c).setValue("student " +(c-1) + " name");
  }

  // printing out first cell in table
  printSheet.getRange(1, 1).setValue("mentor names");

  // searching function for existing students in mentors arrays - returns boolean
  function existsInArray(searchArray, term){
    var result = false;
    for(var i=1; i<searchArray.length; i++){
      if (searchArray[i] == term){
        result = true;
        break;
      }
    }
    return result;
  }

  // searching function for existing mentors in main array - returns undefined or key of found value
  function findMentor(searchArray, name){
    var result = undefined;
    for(var i=0; i<searchArray.length; i++){
      if (searchArray[i][0] == name){
        result = i;
        break;
      }
    }
    return result;
  }

  Logger.log(foundMentors.toString());
  Logger.log(' pushedMentors: ' +pushedMentors+ ' studentsPushed: '+studentPushed+ '  steps: '+step);
}