How to export csv file in php (code example)

/**  如果大量数据导出 支持分页写入
	 * [DownloadDate 公共导出csv]
	 * @param  string                   $name   [文件名称]
	 * @param  array                   $header [表头]
	 * @param  array                    $data   [数据集]
	 * @param                      $is_header   [真 假 是否取表头 解决循环写入问题]
	 * @return array             name[文件名称]   filePath[文件路径]                               
	 */
	public static function DownloadData($name='',$header=array(),$data=array(),$is_header=true){
      	set_time_limit(0);
      	ini_set('memory_limit','2048M'); 
      	header("Content-type:application/vnd.ms-excel");
      	header("content-Disposition:filename=downloaded.pdf ");
      	try {
      		if (!$name || !$data) {
      			throw new BadRequestHttpException('参数不可为空');
      		}
	      	$filePath = "./temp/download/{$name}.csv";
	      	$header = implode(",",$header);
	      	$header = iconv('UTF-8', 'GBK//IGNORE', $header);
	      	$header = explode(",", $header);
	      	$fp = fopen($filePath, 'a+');   
	      	if (!empty($header) && is_array($header) && $is_header) {
	      		fputcsv($fp, $header);
	      	}
	      	foreach ($data as $row) {
	      		$str = implode("@@@@",$row);
	      		$str = iconv('UTF-8', 'GBK//IGNORE', $str);
	      		$str = str_replace(",","|",$str);
	      		$row = explode("@@@@", $str);
	      		fputcsv($fp, $row);
	      	}
	      	unset($data);  
	      	if(ob_get_level()>0){
	      		ob_flush();
	      	}  
	      	flush(); 	
      	} catch (Exception $e) {
      		 throw new BadRequestHttpException($e->getMessage());//抛出异常
      	}
      	return [
      	'filePath'=>ltrim($filePath,"./"),
      	'name'=>$name.'.csv',
      	];
 	}