Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

How to substitute 
<p></p> # For the character <.

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If character 
'>'

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exists at the end of the character <.
As in the data for a href..... <p></p> should not be substituted. 

#!/usr/bin/perl
while (<DATA>) {
if($_ =~ /<.+>(<.+>)(.*)/){
              $output = $1.$2;
$output =~ s/(<|\\)/<\/p><p>/g;
print $output;
}
}
__DATA__
<BODY><![CDATA[<p>Developmentally, 2-year-olds are generally more inte
+rested in themselves, while dogs do care how their people feel, and i
+nstantly recognize a change in emotion.< "While your dog can't compre
+hend that you just received a traffic violation, he can tell that you
+'re upset the second you walk through the door," Coren says. "In fact
+, dogs can detect some subtle changes which even adults can't," adds 
+Coren. "We can't smell cancer or predict seizures, as dogs can."< Whe
+n I posted this story on my Facebook Fan page recently (<a href="http
+://www.new.facebook.com/pages/ Steve-Dale/50057343596?ref=ts">www.new
+.f acebook.com/pages/Steve-Dale/50057343596?ref=ts, or simply type St
+eve Dale into the Facebook search), I received some interesting respo
+nses:< Kelle: "Heck, my Italian Greyhound is smarter than most colleg
+e students."< Karen: "Depends on how you define smart.

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Replies are listed 'Best First'.
Re: p tag substitution
by GrandFather (Saint) on Oct 15, 2009 at 08:01 UTC

    Do not use regexen to parse markup - life if just too short to bother reinventing that particular wheel. Use a suitable HTML module. See Re: Some portion of the text missing for example.

    True laziness is hard work
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      How to check if > exists after the  < and then substitute < with </p><p> For example : 
      <a ahref="http://www.prospect.org/cs/articles?articleId=11945">

# Here < should not be replaced with </p><p>

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        if ($code =~ /=~/ && $data =~ /<p>/) {
    print "Woe unto you!\n"
}

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        True laziness is hard work
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Re: p tag substitution
by Marshall (Canon) on Oct 15, 2009 at 10:48 UTC
    I didn't know in the first thread what you wanted to do, "text is missing" was not very informative!

    Parsing this HTML stuff can get complicated and I would agree with GrandFather that an HTML module is best for complex situations.

    But....here is a one regex way of doing it (that seems to be what you want). This is only 5, "non-trivial" lines of code, but it did take me some time to write them. There is of course some stuff that is specific to your application and the example that I had!

    #!/usr/bin/perl -w
use strict;

use constant DEBUG => 1; #makes lines easier to see on screen

while (<DATA>) 
{
   if ( my ($title, $body) = 
         ($_ =~ /<TITLE>.*?(<p>.+?)<BODY>.*?(<p>.*)/)[0,1]
      )
   {

      $title .= "</p>";
      $body  .= "</p>";
      
      $title =~ s|<[^a/p]|<p>|g;    
      $title =~ s|.<p>|.</p><p>|g;
      $title =~ s|</p>|</p>\n|g if DEBUG;
      
      $body =~ s|<[^a/p]|<p>|g;
      $body =~ s|.<p>|.</p><p>|g;
      $body =~ s|</p>|</p>\n|g if DEBUG;
      
      print "<TITLE>\n$title\n\n",
            "<BODY>\n$body\n"; 
   }
}

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    With DEBUG on, this prints: 
    <TITLE>
<p>Dogs may not smarter than 6-year-olds, but researchers suggest cani
+nes might be on par with 2-year-olds.</p>
<p>Psychologist Stanley Coren says, "We do know that dogs understand f
+ar more than we credit them with, from about 165 words to 250 words."
+ Even better than understanding our words, dogs know our hand gesture
+s and body postures. Dogs may, in fact, far exceed 2-year-olds when i
+t comes to reading emotions.</p>


<BODY>
<p>Developmentally, 2-year-olds are generally more interested in thems
+elves, while dogs do care how their people feel, and instantly recogn
+ize a change in emotion.</p>
<p>"While your dog can't comprehend that you just received a traffic v
+iolation, he can tell that you're upset the second you walk through t
+he door," Coren says. "In fact, dogs can detect some subtle changes w
+hich even adults can't," adds Coren. "We can't smell cancer or predic
+t seizures, as dogs can..</p>
<p>When I posted this story on my Facebook Fan page recently (<a href=
+"http://www.new.facebook.com/pages/ Steve-Dale/50057343596?ref=ts">ww
+w.new.f acebook.com/pages/Steve-Dale/50057343596?ref=ts, or simply ty
+pe Steve Dale into the Facebook search), I received some interesting 
+responses.</p>
<p>Kelle: "Heck, my Italian Greyhound is smarter than most college stu
+dents..</p>
<p>Karen: "Depends on how you define smart.</p>

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Re: p tag substitution
by ww (Archbishop) on Oct 15, 2009 at 12:29 UTC

    Since you didn't show us desired output, I suspect your spec if faulty because what you show would not result in reasonable .html.

    So, taking a guess (possibly wrong), if you're looking for this:

    <p>Developmentally, 2-year-olds are generally more interested in thems
+elves, while dogs do care how their people feel, and instantly recogn
+ize a change in emotion.</p>

<p>"While your dog can't comprehend that you just received a traffic v
+iolation, he can tell that you're upset the second you walk through t
+he door," Coren says. "In fact, dogs can detect some subtle changes w
+hich even ad
ults can't," adds Coren. "We can't smell cancer or predict seizures, a
+s dogs can."</p>

<p>When I posted this story on my Facebook Fan page recently (<a href=
+"http://www.new.facebook.com/pages/ Steve-Dale/50057343596?ref=ts">ww
+w.new.f acebook.com/pages/Steve-Dale/50057343596?ref=ts, or simply ty
+pe Steve Dal
e into the Facebook search), I received some interesting responses:</p
+>

<p>Kelle: "Heck, my Italian Greyhound is smarter than most college stu
+dents."</p>

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    you could do this to the data you supplied (which, IMO, implies that you want to replace only those "<" which are followed directly by a space):

    #!/usr/bin/perl
use strict;
use warnings;

my $output;
while (<DATA>) {
    if ($_ =~ /<.+>(<.+>)(.*)/){
        $output = $1.$2;
            $output =~ s/<!\[CDATA\[(.*)/$1/;
            # print $output;
    }
    print "\n\n";

    $output =~ s!(< )!</p>\n\n<p>!g;
    print $output . '</p>' . "\n";
}

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    But, as GrandFather said,

    DON'T DO THIS!
    There are too many corner cases, "gotchas," and other complications to make "rolling your own" profitable.

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