PHP range() from A to ZZ?

for ($i = 'A'; $i !== 'AC'; $i++){
    echo $i.', '; //A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, AA, AB,
}

it's working

Just Try this- (tested working fine)

function createColumnsArray($end_column, $first_letters = '')
{
  $columns = array();
  $length = strlen($end_column);
  $letters = range('A', 'Z');

  // Iterate over 26 letters.
  foreach ($letters as $letter) {
      // Paste the $first_letters before the next.
      $column = $first_letters . $letter;

      // Add the column to the final array.
      $columns[] = $column;

      // If it was the end column that was added, return the columns.
      if ($column == $end_column)
          return $columns;
  }

  // Add the column children.
  foreach ($columns as $column) {
      // Don't itterate if the $end_column was already set in a previous itteration.
      // Stop iterating if you've reached the maximum character length.
      if (!in_array($end_column, $columns) && strlen($column) < $length) {
          $new_columns = createColumnsArray($end_column, $column);
          // Merge the new columns which were created with the final columns array.
          $columns = array_merge($columns, $new_columns);
      }
  }

  return $columns;
}
echo "<pre>";
print_r( createColumnsArray('BZ'));

copied from http://php.net/range

Take advantage of PHP's ability to increment characters "perl-style"

$letters = array();
$letter = 'A';
while ($letter !== 'AAA') {
    $letters[] = $letter++;
}

But you could also use simple integer values, and take advantage of PHPExcel's built-in PHPExcel_Cell::stringFromColumnIndex() method

EDIT

From PHP 5.5, you can also use Generators to avoid actually building the array in memory

function excelColumnRange($lower, $upper) {
    ++$upper;
    for ($i = $lower; $i !== $upper; ++$i) {
        yield $i;
    }
}

foreach (excelColumnRange('A', 'ZZ') as $value) {
    echo $value, PHP_EOL;
}