Send email using Google Apps Script, with filename in spreadsheet

Question

I'm trying to do the same thing as this question:

Send an email with attachment using Google Apps Script

But with the attachment names as cells in the spreadsheet. My code is here:

function sendEmailsandAttachments() {
  var sheet = SpreadsheetApp.getActiveSheet();
  var startRow = 1; // First row of data to process
  var numRows = 3; // Number of rows to process
  // Fetch the range of cells A2:B3
  // Need to extend this. That 1 3 is starting, ending columns!
  var dataRange = sheet.getRange(startRow, 1, numRows, 3);
  // Fetch values for each row in the Range.
  var data = dataRange.getValues();
  for (var i in data) {
    var row = data[i];
    var emailAddress = row[0]; // First column
    var message = row[1]; // Second column
    var examname = row[2];
    var full_examname = "Teaching/PHY2211/Exams/" + examname;
    Logger.log(full_examname);
    //var file = row[2]; //third column
    var file = DriveApp.getFilesByName(full_examname).next();
    var subject = 'Sending emails from a Spreadsheet';
    MailApp.sendEmail(emailAddress, subject, message, {attachments: file} );
  }
}

I can see in the log that my filenames are actually working, but I just get "cannot retreive the next object: iterator". My guess is I don't understand exactly why .next() is there (because I don't), but it seems like attachments is expecting some kind of array, but I just want to pass a single file to it.

Answer 1

Replace

var file = DriveApp.getFilesByName(full_examname).next();
var subject = 'Sending emails from a Spreadsheet';
MailApp.sendEmail(emailAddress, subject, message, {attachments: file} );

by

var subject = 'Sending emails from a Spreadsheet';
var files =  DriveApp.getFilesByName(full_examname);
if(files.hasNext()){
   var file = files.next();
   MailApp.sendEmail(emailAddress, subject, message, {attachments: file} );
} else {
  // Put here what you want that the code do when no file is found.
}

Brief explanation

getFilesbyName returns a file iterator. next() it's there to get the file referred by the file iterator but it will only work if a file was found. hasNext() should be there to check if a file was found.