PHP data export case analysis

<?php
 
$list = array (
  array(&#39;aaa&#39;, &#39;bbb&#39;, &#39;ccc&#39;, &#39;dddd&#39;),
  array(&#39;123&#39;, &#39;456&#39;, &#39;789&#39;),
  array(&#39;"aaa"&#39;, &#39;"bbb"&#39;)
);
 
$fp = fopen(&#39;file.csv&#39;, &#39;w&#39;);
 
foreach ($list as $fields) {
  fputcsv($fp, $fields);
}
 
fclose($fp);
?>

<?php
 
$name = &#39;test&#39;;
header ( "Content-type:application/vnd.ms-excel" );
header ( "Content-Disposition:filename=".$name.".csv" );
header (&#39;Cache-Control: max-age=0&#39;);
 
//打开PHP文件句柄，php://output 表示直接输出到浏览器
$fp = fopen(&#39;php://output&#39;, &#39;a&#39;);  
 
// 写入BOM头，防止乱码
fwrite($fp, chr(0xEF).chr(0xBB).chr(0xBF)); 
 
// 生成的测试数据
function test()
{
  for ($i=0; $i < 150000; $i++) {
    yield [&#39;name&#39;, $i, &#39;男&#39;];
  }
}
 
// 表头
$headers = [&#39;名字&#39;, &#39;年龄&#39;, &#39;性别&#39;];
 
fputcsv($fp, $headers);
 
foreach (test() as $value) {
  fputcsv($fp, $value);
}
 
fclose($fp);
?>