php中实现产品展示$classify=array("")方法如何将产品介绍分类添加进txt文件中

已实现通过读取txt文档进行产品展示，如何跟据不同产品种类分类添加产品介绍？

plantslist.txt:
<?php
$plantsclassify=array("产品种类","产品种类","产品种类");
$产品种类=array(array("产品名称","介绍",价格),array("名称","介绍",价格),array("名称","介绍",价格));
$产品种类=array(array("产品名称","介绍",价格),array("名称","介绍",价格),array("名称","介绍",价格));
$产品种类=array(array("产品名称","介绍",价格),array("名称","介绍",价格),array("名称","介绍",价格));
?>

<?php

include("plantslist.txt");
foreach($plantsclassify as $classify)
{
echo "$classify ";
}
echo "查看购物车";
if(isset($_GET["catalog"]))
{
$catalog=$_GET["catalog"];
$_SESSION["catalog"]=$catalog;
echo "

";
echo "";
echo "";
echo "";
echo "";
echo "";
echo "";
echo "";
foreach($$catalog as $plants)
{
echo "";
foreach ($plants as $val)
{
echo "";
}
echo "";
echo "";
}
echo "";
echo "";
echo "";
echo "

植物名	详细信息	价格	购买
$val

";
echo "";
}
if(isset($_GET["success"]))
{
if($_GET["success"]==0)
{
echo "alert(&#39;请选购植物&#39;)";
}
if($_GET["success"]==1)
{
echo "alert(&#39;已加入购物车！&#39;)";
}
}
?>

这也能叫读取txt? 不如直接改成php文件好了。
操作文件读写需要fopen fread fwrite