怎么提取perl匹配上的字符串？

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我想提取部分网页中的ftp地址，写了如下脚本，可是在输出的时候，$1总是空的。

1. #!/usr/bin/perl
   
2. for($i=34271;$i<34380;$i++)
   
3. {
   
4.         $url = "http://www.ffdy.cc/movie/$i.html";
   
5.         use LWP::Simple;
   
6.         $content = get $url;
   
7. #       die "Couldn't get $url" unless defined $content;
   
8.         if($content =~ m/ftp.*rmvb/is)
   
9.         {
   
10.                 print "page $i ok\n";
    
11.                 $tmp=$1;
    
12.                 print "$tmp\n";
    
13.         }
    
14.         else
    
15.         {
    
16.                 print "page $i no\n";
    
17.         }
    
18. }
    

复制代码

能用$1提取匹配后的字符串吗？结果总是空的……希望大家给我指点，谢谢

ziyunfei

if($content =~ m/ftp.*?rmvb/is)
        {
                print "page $i ok\n";
                $tmp=$&;

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回复 2# ziyunfei


    太感谢了！

albertd

Programming Perl

Each time a pattern successfully matches (including the pattern in a substitution), it sets the $`, $&, and $' variables to the text left of the match, the whole match, and the text right of the match. This is useful for pulling apart strings into their components

For better granularity and efficiency, use parentheses to capture the particular portions that you want to keep around. Each pair of parentheses captures the substring corresponding to the subpattern in the parentheses. The pairs of parentheses are numbered from left to right by the positions of the left parentheses; the substrings corresponding to those subpatterns are available after the match in the numbered variables, $1, $2, $3, and so on