Question

PHP代码部分不是很清楚 高手求解，求理解

<?php
session_start();
header ( "Content-type: text/html; charset=UTF-8" ); //设置文件编码格式
require("system/system.inc.php"); //包含配置文件

$reback = '0';

$commid = explode(',',$_GET['rd']);

$newshop = array();

$sql = "select id,shopping from tb_user where name = '".$_SESSION['member']."'";
$rst = $admindb->ExecSQL($sql,$conn);
if($rst==false){
$reback = '2';
}else{

if(!empty($rst[0]['shopping'])){
$tmpshop = array();
$shopping = explode('@',$rst[0]['shopping']);
foreach($shopping as $ky => $vl){
$tmp = explode(',',$vl);
$boo = false;
foreach($commid as $value){
if($value == $tmp[0]){
$boo = true;
}
}
if(!$boo){
$tmpshop[$ky] = $vl;
}
}
if(!empty($tmpshop)){
$update = "update tb_user set shopping='".implode('@',$tmpshop)."' where name = '".$_SESSION['member']."'";
}else{
$update = "update tb_user set shopping='' where name = '".$_SESSION['member']."'";
}
$shop = $admindb->ExecSQL($update,$conn);
if($shop){
$reback = 1;
}else{
$reback = 3;
}
}
}
echo $reback;
?>

这部分怎么解释
f(!empty($rst[0]['shopping'])){
$tmpshop = array();
$shopping = explode('@',$rst[0]['shopping']);
foreach($shopping as $ky => $vl){怎么解释
$tmp = explode(',',$vl);怎么解释
$boo = false;怎么解释
foreach($commid as $value){
if($value == $tmp[0]){怎么解释
$boo = true;怎么解释}
}
if(!$boo){怎么解释
$tmpshop[$ky] = $vl;怎么解释
}
if(!empty($tmpshop)){
$update = "update tb_user set shopping='".implode('@',$tmpshop)."' where name = '".$_SESSION['member']."'";这部分怎么解释

Answer 1

简单给你说一下
empty()函数，检测变量是否为空，是空就返回true，否则返回false
foreach循环，遍历一个数组
explode()函数，将字符串以特定的分隔符打散成数组
if语句，对特定的条件进行判断
!感叹号，表示否定，相反的意思
[]方括号，对数组元素的访问
implode()函数，以特定的字符将数组转换成字符串

建议你还是从php最基本的开始学起吧，看你的提问，似乎你对php还没有一点基础就来研究成片的代码了，走都不会，咋能飞呢！
比如：php的基本语法、基本函数的应用等等开始学起！

Answer 2

你才接触PHP编程吧，这是最基本的东西了，强烈建议你先找本PHP入门的书好好看看，然后再开始编程、读代码