求段php 替换输出的代码

Question

循环那部分一直写不对
要求如下
读取a.txt内容是
111,2222
333,4444
555,7777
这样的格式
如果$goods_id的值等于其中一行前面的值那么转换成后面的输出，比如$goods_id=111,那么进行替换后输出$goods_id=2222

Answer 1

$goods_id=111;$handle=fopen("f:/test.txt","r");while(!feof($handle)){$line=fgets($handle,4096);//echo$line."";$str=explode(",",$line);if($str[0]==$goods_id){echo$str[1];}}fclose($handle);

Answer 2

`functiongetGoodsIpMap(){$fh=fopen('a.txt','r');$goodsMap=array();while($line=fgets($fh)!==false){if(empty($line)){continue;}list($oldId,$newId)=explode(',',trim($line));$goodsMap[$oldId]=$newId;}fclose($fh);}$goodsIdMap=getGoodsIpMap();$newId=isset($goodsIdMap[$goodsId])?$goodsIdMap[$goodsId]:$goodsId;`