为什么匹配运算符不匹配任何内容？

Question

我正在尝试解析这个HTML块:

<div class="v120WrapperInner"><a href="/redirect?q=http%3A%2F%2Fwww.google.com%2Faclk%3Fsa%3DL%26ai%3DCKJh--O7tSsCVIKeyoQTwiYmRA5SnrIsB1szYhg2d2J_EAhABIJ7rxQ4oA1CLk676B2DJntmGyKOQGcgBAaoEFk_Qyu5ipY7edN5ETLuchKUCHbY4SA#0%26num%3D1%26sig%3DAGiWqtwtAf8NslosN7AuHb7qC7RviHVg7A%26q%3Dhttp%3A%2F%2Fwww.youtube.com%2Fwatch%253Fv%253D91sYT_8CN8Q%2526feature%253Dpyv%2526ad%253D3409309746%2526kw%253Dsusan%25252#0boyle&amp;adtype=pyv&amp;event=ad&amp;usg=bR7ErKA_3szWtQMGe2lt1dpxzHc=" title="The Valley Downs Chicago"><img class="vimg120" alt="The Valley Downs Chicago" src="http://i2.ytimg.com/vi/91sYT_8CN8Q/1.jpg">

捕获重定向链接:

/redirect?q=http%3A%2F%2Fwww.google.com%2Faclk%3Fsa%3DL%26ai%3DCKJh--O7tSsCVIKeyoQTwiYmRA5SnrIsB1szYhg2d2J_EAhABIJ7rxQ4oA1CLk676B2DJntmGyKOQGcgBAaoEFk_Qyu5ipY7edN5ETLuchKUCHbY4SA#0%26num%3D1%26sig%3DAGiWqtwtAf8NslosN7AuHb7qC7RviHVg7A%26q%3Dhttp%3A%2F%2Fwww.youtube.com%2Fwatch%253Fv%253D91sYT_8CN8Q%2526feature%253Dpyv%2526ad%253D3409309746%2526kw%253Dsusan%25252#0boyle&adtype=pyv&event=ad&usg=bR7ErKA_3szWtQMGe2lt1dpxzHc=

和视频标题:

The Valley Downs Chicago

当我使用这个简单的Perl代码时:

foreach $_ (@promotedVideos)
{
   if (/\s<div class="v120WrapperInner"><a href="([^"]*)" title="([^"]*)"><img/six)
   {
     print $1;
     print $2;
   }
}

没有打印.虽然我正在对此进行故障排除,但我想如果您发现任何错误或有问题,我会问您专家.非常感谢您的帮助!

Answer 1

你的/ x正则表达式修饰符会混淆空格.去掉它.

也就是说,它应该是

if (/\s<div class="v120WrapperInner"><a href="([^"]*)" title="([^"]*)"><img/si)

/ x使perl忽略正则表达式中的空格,使你的正则表达式相当于以下内容:

/\s<divclass="v120WrapperInner"><a href="([^"]*)"title="([^"]*)"><img/six

那是不匹配的.

在开始的时候也可能会制造东西.

这是我用于测试的代码:

use strict;


my $inp = '<div class="v120WrapperInner"><a href="/redirect?q=http%3A%2F%2Fwww.google.com%2Faclk%3Fsa%3DL%26ai%3DCKJh--O7tSsCVIKeyoQTwiYmRA5SnrIsB1szYhg2d2J_EAhABIJ7rxQ4oA1CLk676B2DJntmGyKOQGcgBAaoEFk_Qyu5ipY7edN5ETLuchKUCHbY4SA#0%26num%3D1%26sig%3DAGiWqtwtAf8NslosN7AuHb7qC7RviHVg7A%26q%3Dhttp%3A%2F%2Fwww.youtube.com%2Fwatch%253Fv%253D91sYT_8CN8Q%2526feature%253Dpyv%2526ad%253D3409309746%2526kw%253Dsusan%25252#0boyle&amp;adtype=pyv&amp;event=ad&amp;usg=bR7ErKA_3szWtQMGe2lt1dpxzHc=" title="The Valley Downs Chicago"><img class="vimg120" alt="The Valley Downs Chicago" src="http://i2.ytimg.com/vi/91sYT_8CN8Q/1.jpg">';

print "$inp\n";

if ( $inp =~ /<div class="v120WrapperInner"><a href="([^"]*)" title="([^"]*)"><img/si )
{
 print "m:\n$1\n$2\n";
}