一段代码执行问题

Question

<?php 
$DBserver         = "localhost";
$DBname           = "new";
$DBuser           = "root";
$DBpassword       = "";
$con = mysql_connect("localhost","root","");
mysql_query("set names 'gbk'");
mysql_select_db("new");
$query = mysql_query("select page_id,page_text from pagecontents where page_id = 101370") or die(mysql_error() );
while($rows = mysql_fetch_array($query))
{
$pid = $rows['page_id'];
$ptext = $rows['page_text'];
//部分page_text
//<img src="../Documents/medies/ESIL_zhaoqifadianrelianghuishou.gif" alt="Image:ESIL_zhaoqifadianrelianghuishou.gif" width="850" height="600" longdesc="/index.php/Image:ESIL_zhaoqifadianrelianghuishou.gif" />
//<img src="../Documents/medies/ESIL_gaowenjiayarechuliliucheng1.gif" alt="Image:ESIL_gaowenjiayarechuliliucheng1.gif" width="550" height="400" longdesc="/index.php/Image:ESIL_gaowenjiayarechuliliucheng1.gif" />
preg_match_all('#width="(\d+)"\s*height="(\d+)"#i',$ptext,$m);
if($m[1]>805){
$h=($m[2]*805)/$m[1] ;
$k=805;
    $ptext = preg_replace('/(width=)"(\d+)"(\s*height=)"(\d+)"/i','$1"'.$k.'"$3"'.$h.'"',$m);
}
mysql_query("set names 'gbk'");
$sql = "update pagecontents set page_text = ('{$ptext}') where page_id = ('{$pid}')";
mysql_query($sql) or die(mysql_error());
}
?>
结果是2句都执行了
//部分page_text
//<img src="../Documents/medies/ESIL_zhaoqifadianrelianghuishou.gif" alt="Image:ESIL_zhaoqifadianrelianghuishou.gif" width="805" height="568" longdesc="/index.php/Image:ESIL_zhaoqifadianrelianghuishou.gif" />
//<img src="../Documents/medies/ESIL_gaowenjiayarechuliliucheng1.gif" alt="Image:ESIL_gaowenjiayarechuliliucheng1.gif" width="805" height="568" longdesc="/index.php/Image:ESIL_gaowenjiayarechuliliucheng1.gif" />本来想做的是只改width超过805的那条，也就是第一条，结果所有的都被替换了。

Answer 1

<?php 
$DBserver         = "localhost";
$DBname           = "new";
$DBuser           = "root";
$DBpassword       = "";
$con = mysql_connect("localhost","root","");
mysql_query("set names 'gbk'");
mysql_select_db("new");
$query = mysql_query("select page_id,page_text from pagecontents where page_id = 101370") or die(mysql_error() );
while($rows = mysql_fetch_array($query))
{
    $pid = $rows['page_id'];
    $ptext = $rows['page_text'];
//部分page_text    
//<img src="../Documents/medies/ESIL_zhaoqifadianrelianghuishou.gif" alt="Image:ESIL_zhaoqifadianrelianghuishou.gif" width="850" height="600" longdesc="/index.php/Image:ESIL_zhaoqifadianrelianghuishou.gif" />    
//<img src="../Documents/medies/ESIL_gaowenjiayarechuliliucheng1.gif" alt="Image:ESIL_gaowenjiayarechuliliucheng1.gif" width="550" height="400" longdesc="/index.php/Image:ESIL_gaowenjiayarechuliliucheng1.gif" />  
          preg_match_all('#width="(\d+)"\s*height="(\d+)"#i',$ptext,$m);
//$m[1]是width的值 , $m[2]是height的值。
    if($m[1]>805){
        $h=($m[2]*805)/$m[1] ;
        $k=805;        $ptext = preg_replace('/(width=)"(\d+)"(\s*height=)"(\d+)"/i','$1"'.$k.'"$3"'.$h.'"',$m);
    }
    mysql_query("set names 'gbk'");
    $sql = "update pagecontents set page_text = ('{$ptext}') where page_id = ('{$pid}')";
    mysql_query($sql) or die(mysql_error());
}
?>

Answer 2

$m[1] 返回的是所有匹配的内容.print_r 看看你就知道了

Answer 3

preg_match_all('#width="(\d+)"\s*height="(\d+)"#i',$ptext,$m);
//数组组合成字符串
$m[1]=join(" ",$m[1]);
$m[2]=join(" ",$m[2]);
//$m[1]是width的值 , $m[2]是height的值。
    if($m[1]>805){
        $h=($m[2]*805)/$m[1] ;
        $k=805;        $ptext = preg_replace('/(width=)"(\d+)"(\s*height=)"(\d+)"/i','$1"'.$k.'"$3"'.$h.'"',$m);
    }

Answer 4

记得我给你写贴过代码$page_text =<<< TXT
<img src="../Documents/medies/ESIL_zhaoqifadianrelianghuishou.gif" alt="Image:ESIL_zhaoqifadianrelianghuishou.gif" width="850" height="600" longdesc="/index.php/Image:ESIL_zhaoqifadianrelianghuishou.gif" />    
<img src="../Documents/medies/ESIL_gaowenjiayarechuliliucheng1.gif" alt="Image:ESIL_gaowenjiayarechuliliucheng1.gif" width="550" height="400" longdesc="/index.php/Image:ESIL_gaowenjiayarechuliliucheng1.gif" />  
TXT;echo preg_replace_callback('#width="(\d+)"\s*height="(\d+)"#i', 'back', $page_text );//$m[1]是width的值 , $m[2]是height的值。
function back($m) {
    if($m[1]>805){
        $h=round(($m[2]*805)/$m[1]);
        $k=805;        return "width=\"$k\" height=\"$h\" ";
    }
    return $m[0];
}
<img src="../Documents/medies/ESIL_zhaoqifadianrelianghuishou.gif" alt="Image:ESIL_zhaoqifadianrelianghuishou.gif" width="805" height="568"  longdesc="/index.php/Image:ESIL_zhaoqifadianrelianghuishou.gif" />    
<img src="../Documents/medies/ESIL_gaowenjiayarechuliliucheng1.gif" alt="Image:ESIL_gaowenjiayarechuliliucheng1.gif" width="550" height="400" longdesc="/index.php/Image:ESIL_gaowenjiayarechuliliucheng1.gif" />  

Answer 5

Warning: preg_replace_callback() [function.preg-replace-callback]: Requires argument 2, 'back', to be a valid callback in :
echo preg_replace_callback('#width="(\d+)"\s*height="(\d+)"#i', 'back', $page_text );

Answer 6

<?php 
$DBserver         = "localhost";
$DBname           = "new";
$DBuser           = "root";
$DBpassword       = "";
$con = mysql_connect("localhost","root","");
mysql_query("set names 'gbk'");
mysql_select_db("new");
$query = mysql_query("select page_id,page_text from pagecontents where page_id = 101370") or die(mysql_error() );
while($rows = mysql_fetch_array($query))
{
$pid = $rows['page_id'];
$ptext = $rows['page_text'];

//部分page_text($ptext)
//<img src="../Documents/medies/ESIL_zhaoqifadianrelianghuishou.gif" alt="Image:ESIL_zhaoqifadianrelianghuishou.gif" width="850" height="600" longdesc="/index.php/Image:ESIL_zhaoqifadianrelianghuishou.gif" />
//<img src="../Documents/medies/ESIL_gaowenjiayarechuliliucheng1.gif" alt="Image:ESIL_gaowenjiayarechuliliucheng1.gif" width="550" height="400" longdesc="/index.php/Image:ESIL_gaowenjiayarechuliliucheng1.gif" />
//<img src="../Documents/medies/ESIL_shishiranshao.gif" alt="Image:ESIL_shishiranshao.gif" width="850" height="600" longdesc="/index.php/Image:ESIL_shishiranshao.gif" />
preg_match_all('#width="(\d+)"\s*height="(\d+)"#i',$ptext,$m);
$m[1]=join(" ",$m[1]);
$m[2]=join(" ",$m[2]);
function back($m){
if($m[1]>805){
$h=round(($m[2]*805)/$m[1]);
$k=805;
return  "width=\"$k\" height=\"$h\" ";
}
return $m[0];
}
    $ptext = preg_replace_callback('#width="(\d+)"\s*height="(\d+)"#i','back', $ptext );
mysql_query("set names 'gbk'");
$sql = "update pagecontents set page_text = ('{$ptext}') where page_id = 101370";
mysql_query($sql) or die(mysql_error());
}
?>这样解决了。