求过滤alt的正则表达式

Question

求PHP过滤alt的正则表达式，alt有三种情况，要求都能过滤掉
alt="xxxxxxxxxxxx"
alt='xxxxxxxxxxxx'
alt=xxxxxxxxxxxx要求能过滤掉以上三种情况的。
示例：
<img src="xxxx" alt="xxxxxxxxx" >
<img alt="xxxxxxxx" src="xxxxxxxx">
<img src="xxxxxx" alt=xxxxxxx >
<img alt=xxxxxxxxxxx src="xxxxxxx">
<img src='xxxx' alt='xxxxxxxxx' >
<img alt='xxxxxxxx' src='xxxxxxxx'>……要求能过滤各种情况，又不会过滤其它内容。谢谢。
正则表达式php

Answer 1

$s =<<< TXT
<img src="xxxx" alt="xxxxxxxxx" >
<img alt="xxxxxxxx" src="xxxxxxxx">
<img src="xxxxxx" alt=xxxxxxx >
<img alt=xxxxxxxxxxx src="xxxxxxx">
<img src='xxxx' alt='xxxxxxxxx' >
<img alt='xxxxxxxx' src='xxxxxxxx'>
TXT;echo preg_replace('/alt=([\'"]?).+?\b\1/is', '', $s);
<img src="xxxx"  >
<img  src="xxxxxxxx">
<img src="xxxxxx"  >
<img  src="xxxxxxx">
<img src='xxxx'  >
<img  src='xxxxxxxx'>

Answer 2

$str='<img src="xxxx" alt="xxxxxxxxx" >
<img alt="xxxxxxxx" src="xxxxxxxx">
<img src="xxxxxx" alt=xxxxxxx >
<img alt=xxxxxxxxxxx src="xxxxxxx">
<img src=\'xxxx\' alt=\'xxxxxxxxx\' >';
echo preg_replace('/(.*)(alt=[\"\']?.*?[\"\']?\s+)(.*)/', '$1$3', $str); 

Answer 3

你提供的方法可能只适合我在上面写的例子，我给个实际的的内容，就知道过滤出有问题了。<P align=center><img alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243OF-12228.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243Y40-29608.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243c60-33252.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332440Y0-410N.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332441P-53227.jpg" border=0><BR><BR><img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332442M0-62002.jpg" border=0>&nbsp;&nbsp;<img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332443L0-N248.jpg" border=0>&nbsp;&nbsp;<img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332444I0-X239.jpg" border=0>&nbsp;&nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332445F-953E.jpg" border=0>&nbsp;&nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33244C30-105E1.jpg" border=0></P>

Answer 4

$str='<img src="xxxx" alt="xxxxxxxxx" >
<img alt="xxxxxxxx" src="xxxxxxxx">
<img src="xxxxxx" alt=xxxxxxx >
<img alt=xxxxxxxxxxx src="xxxxxxx">
<img src=\'xxxx\' alt=\'xxxxxxxxx\' >';
echo preg_replace('/(.*)(alt=[\"\']?.*?[\"\']?\s+)(.*)/', '$1$3', $str); 你提供的方法可能只适合我在上面写的例子，我给个实际的的内容，就知道过滤出有问题了。<P align=center><img alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243OF-12228.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243Y40-29608.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243c60-33252.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332440Y0-410N.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332441P-53227.jpg" border=0><BR><BR><img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332442M0-62002.jpg" border=0>&nbsp;&nbsp;<img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332443L0-N248.jpg" border=0>&nbsp;&nbsp;<img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332444I0-X239.jpg" border=0>&nbsp;&nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332445F-953E.jpg" border=0>&nbsp;&nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33244C30-105E1.jpg" border=0></P>

Answer 5

我知道我那个正则有点问题，加那个 \b 是不得已而为之
不过既然能满足你示例的数据，那也就可以了。
你总不能让我去罗列一起可能出现的情况吧？那要你干什么呢？
$s =<<< TXT
<P align=center><img alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243OF-12228.jpg" border=0>
   <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243Y40-29608.jpg" border=0>
   <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243c60-33252.jpg" border=0>
   <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332440Y0-410N.jpg" border=0>
   <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332441P-53227.jpg" border=0><BR><BR>
<img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332442M0-62002.jpg" border=0>
  <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332443L0-N248.jpg" border=0>
  <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332444I0-X239.jpg" border=0>
   <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332445F-953E.jpg" border=0>
   <img  src="/uploads/allimg/c100508/12I33244C30-105E1.jpg" border=0 alt=如果QQ我是你></P>
TXT;
echo preg_replace('/alt=([\'"]?).+?\1(\s|>)/is', '$2', $s);<P align=center><img  src="/uploads/allimg/c100508/12I33243OF-12228.jpg" border=0>
 &nbsp; <img   src="/uploads/allimg/c100508/12I33243Y40-29608.jpg" border=0>
 &nbsp; <img   src="/uploads/allimg/c100508/12I33243c60-33252.jpg" border=0>
 &nbsp; <img   src="/uploads/allimg/c100508/12I332440Y0-410N.jpg" border=0>
 &nbsp; <img   src="/uploads/allimg/c100508/12I332441P-53227.jpg" border=0><BR><BR>
<img   src="/uploads/allimg/c100508/12I332442M0-62002.jpg" border=0>
&nbsp;&nbsp;<img   src="/uploads/allimg/c100508/12I332443L0-N248.jpg" border=0>
&nbsp;&nbsp;<img   src="/uploads/allimg/c100508/12I332444I0-X239.jpg" border=0>
&nbsp;&nbsp; <img   src="/uploads/allimg/c100508/12I332445F-953E.jpg" border=0>
&nbsp;&nbsp; <img  src="/uploads/allimg/c100508/12I33244C30-105E1.jpg" border=0 ></P>

Answer 6

$str='<img src="xxxx" alt="xxxxxxxxx" >
<img alt="xxxxxxxx" src="xxxxxxxx">
<img src="xxxxxx" alt=xxxxxxx >
<img alt=xxxxxxxxxxx src="xxxxxxx">
<img src=\'xxxx\' alt=\'xxxxxxxxx\' >';
echo preg_replace('/(.*)(alt=[\"\']?.*?[\"\']?\s+)(.*)/', '$1$3', $str); 你提供的方法可能只适合我在上面写的例子，我给个实际的的内容，就知道过滤出有问题了。<P align=center><img alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243OF-12228.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243Y40-29608.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243c60-33252.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332440Y0-410N.jpg" border=0> &nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332441P-53227.jpg" border=0><BR><BR><img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332442M0-62002.jpg" border=0>&nbsp;&nbsp;<img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332443L0-N248.jpg" border=0>&nbsp;&nbsp;<img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332444I0-X239.jpg" border=0>&nbsp;&nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332445F-953E.jpg" border=0>&nbsp;&nbsp; <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33244C30-105E1.jpg" border=0></P>

你到底测试我的了没有呢？

Answer 7

$str=<<< TXT
<P align=center><img alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243OF-12228.jpg" border=0>
   <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243Y40-29608.jpg" border=0>
   <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I33243c60-33252.jpg" border=0>
   <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332440Y0-410N.jpg" border=0>
   <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332441P-53227.jpg" border=0><BR><BR>
<img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332442M0-62002.jpg" border=0>
  <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332443L0-N248.jpg" border=0>
  <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332444I0-X239.jpg" border=0>
   <img  alt=如果QQ我是你 src="/uploads/allimg/c100508/12I332445F-953E.jpg" border=0>
   <img  src="/uploads/allimg/c100508/12I33244C30-105E1.jpg" border=0 alt=如果QQ我是你></P>
TXT;
echo preg_replace('/(.*?)(alt=["\']?.*?["\']?)(\s+|>)/', '$1$3', $str); 
忘记靠在后面没有空格的情况了，加上允许在最后没有空格的境况就可以了