Regular expression for parsing multile text in perl

Question

I am parsing one input file which has following content.

   &lt;tr&gt;
 &lt;th width="50%"&gt;ABC&lt;/th&gt;&lt;th width="50%"&gt;XYZ&lt;/th&gt;
   &lt;/tr&gt;
   &lt;tr&gt;       
   &lt;tr&gt;
        &lt;td&gt;avc&lt;/td&gt;
        &lt;td&gt;fds&lt;/td&gt;
   &lt;/tr&gt;

code:

 #!/usr/bin/perl
 open(fh,$ARGV[0]) or die "could not open a file\n";
 $input=<fh>
 #print($input)
 if($input =~ /&lt;tr&gt;(\n)?(.*)(\n)?tr&gt;/)
 { 
     print($1);
 }

But there is no output. How to get middle line having th tag?

ikegami · Accepted Answer · 2013-01-25 08:29:20Z

3

How can you match text that spans multiple lines if you only read one line? Perhaps you were trying to load the entire file, which you can do as follows;

my $input; { local $/; $input = <fh>; }

By the way, always use use strict; use warnings;!

answered Jan 25, 2013 at 8:29

ikegami

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Comments

Orabîg · Accepted Answer · 2013-01-25 08:39:54Z

1

It looks like you're only reading the first line...

Why don't you put your code inside a while loop ?

(Also, getting the entiere file by setting $/ to '' is a better idea as suggested, as you're looking for a pattern matching several lines)

This code works :

 #!/usr/bin/perl
 open(fh,$ARGV[0]) or die "could not open a file\n";
 {
    local $/;
    $input=<fh>;
    if($input =~ /&lt;tr&gt;\s*(.*)\s*&lt;\/tr&gt;/)
     { 
         print($1);
     }
    }

(Notice that I removed the parenthesis around \n which were useless)

However it's not very clean...

Also, why don't you start with :

$input=~s/&lt/</g;
$input=~s/&gt/>/g;

Which will help your code being more readable ?

edited Jan 25, 2013 at 8:39

answered Jan 25, 2013 at 8:29

Orabîg

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1 Comment

Manish Over a year ago

My code has multiline <tr><th></th></tr> <tr><td></td></tr> but above code parse only 'th' tag

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