PHPExcel to generate xls from array

write_excel.php

function erecruitment_export_write_excel( $data, $uri){

  if( count($data) == 0 ) return '';

  // load phpexcel library
  $module_path = drupal_get_path('module', 'erecruitment');
  require_once( $module_path . '/vendor/autoload.php' );

  $doc = new PHPExcel();


  $active_sheet = 0 ;
  foreach( $data as $job_id => $rows ) {
    // Add new sheet
    $doc->createSheet( $active_sheet );
    $doc->setActiveSheetIndex( $active_sheet++ );
    erecruitment_export_write_excel_sheet( $doc, $job_id, $rows);
  }


  // Write The Excel file
  $writer = PHPExcel_IOFactory::createWriter($doc, 'Excel5');
  $writer->save( drupal_realpath( $uri ) );


}

function erecruitment_export_write_excel_sheet( &$doc, $job_id, $data ) {


  // Pre calculate all First Level and Second Level Header
  $header = array();
  foreach( $data as $row ){

    // Loop Through Each row Items
    foreach( $row as $key => $item ) {

      if( ! isset( $header[ $key ] ) ) {
        $header[ $key ] = array(
            'span' => 1,
            'secondary_keys' => array(),
          );
      }

      // If particular row item has an array then consider that as second level
      // then generate 2nd level keys and update 1st level key's cell merge count
      if( is_array( $item) ) {
        foreach( $item as $secondaryKey => $secondaryValue) {
          if( isset( $header[$key]['secondary_keys'][ $secondaryKey]) )   continue;
          $header[$key]['secondary_keys'][ $secondaryKey] = 1;
          $header[$key]['span'] = count( $header[$key]['secondary_keys'] );
        }
      }

    }

  }

  // Print Job Details
  $job_title = 'No Job Selected';

  if( $job_id != 0 ) {
    $job_node = node_load( $job_id );
    $job_title = $job_node->title;
  }

  $doc->getActiveSheet()
    ->setCellValueByColumnAndRow( 0, 1, 'Job Title')
    ->setCellValueByColumnAndRow( 1, 1, $job_title)
    ->mergeCellsByColumnAndRow( 1, 1, 14, 1);


  // Print Header

  $hasSecondaryRow = false;

  $rowIndex = 3;
  $col = 0;

  foreach( $header as $key => $row ) {

    // See If First Level Row as secondary Keys
    if( $row['span'] > 1 or count( $row['secondary_keys']) > 0 ) {

      $hasSecondaryRow = true;

      // In that case merge cells for first level key
      $doc->getActiveSheet()->mergeCellsByColumnAndRow( $col, $rowIndex, ($col + $row['span'] - 1), $rowIndex);
      $sec_key_start = $col;

      // Loop Through to fill Secondary Keys on 2nd row
      foreach( $row['secondary_keys'] as $sec_key => $sec_value ) {
        $doc->getActiveSheet()->setCellValueByColumnAndRow( $sec_key_start++, $rowIndex + 1, $sec_key);
      }
    }

    $doc->getActiveSheet()->setCellValueByColumnAndRow( $col, $rowIndex, $key);

    $col += $row['span'];

  }

  // Now check if there is any secondary header. If yes, then increase data row count by 1
  $rowIndex = $hasSecondaryRow ?  ( $rowIndex + 2) : ( $rowIndex + 1) ;

  // Print Actual Data
  foreach( $data as $row ){

    $column = 0;

    // Loop Through Header
    foreach( $header as $key => $item ) {

      // If header has more than one secondary item then traverse 2nd level
      if( $item['span'] > 1 or count( $item['secondary_keys']) > 0 ) {

        foreach( $item['secondary_keys'] as $sec_key => $value ) {
          $doc->getActiveSheet()->setCellValueByColumnAndRow( $column++, $rowIndex,
              isset( $row[ $key ][ $sec_key ] ) ? $row[ $key ][ $sec_key ] : '' );
        }
      }
      // Else this is a single level header so just print out data
      else {
        $doc->getActiveSheet()->setCellValueByColumnAndRow( $column++, $rowIndex,
            isset( $row[ $key ] ) ? $row[ $key ]  : '' );
      }
    }

    $rowIndex++;

  }


}