use strict;
my $str = '<div class="question-summary" id="question-summary-80407">
<div class="statscontainer">
<div class="statsarrow"></div>
<div class="stats">
<div class="vote">
<div class="votes">
<span class="vote-count-post "><strong>2</strong></span>
<div class="viewcount">votes</div>
</div>
</div>
<div class="status answered">
<strong>1</strong>answer
</div>
</div>
<div class="views " title="60 views">
60 views
</div>
</div>
<div class="summary">
<h3><a href="/questions/80407/about-power-supply-of-opertional-amplifier" class="question-hyperlink">about power supply of opertional amplifier</a></h3>
<div class="excerpt">
I am constructing an operational amplifier as shown in the following figure. I use a batter as supplier for the OP Amp and set it up as a non-inverting amp circuit. I saw that the output was clipped ...
</div>
<div class="tags t-op-amp">
<a href="/questions/tagged/op-amp" class="post-tag" title="show questions tagged \'op-amp\'" rel="tag">op-amp</a>
</div>
<div class="started fr">
<div class="user-info ">
<div class="user-action-time">
asked <span title="2013-08-27 21:49:14Z" class="relativetime">11 hours ago</span>
</div>
<div class="user-gravatar32">
<a href="/users/17060/user1285419"><div class=""><img src="https://www.gravatar.com/avatar/08ee68b20a4eceff26f7eee99b708c08?s=32&d=identicon&r=PG" alt="" width="32" height="32"></div></a>
</div>
<div class="user-details">
<a href="/users/17060/user1285419">user1285419</a><br>
<span class="reputation-score" title="reputation score" dir="ltr">165</span><span title="5 bronze badges"><span class="badge3"></span><span class="badgecount">5</span></span>
</div>
</div>
</div>
</div>
</div>
<div class="question-summary" id="question-summary-80405">
<div class="statscontainer">
<div class="statsarrow"></div>
<div class="stats">
<div class="vote">
<div class="votes">
<span class="vote-count-post "><strong>4</strong></span>
<div class="viewcount">votes</div>
</div>
</div>
<div class="status answered-accepted">
<strong>2</strong>answers
</div>
</div>
<div class="views " title="64 views">
64 views
</div>
</div>
<div class="summary">
<h3><a href="/questions/80405/5v-regulator-power-dissipation" class="question-hyperlink">5V Regulator Power Dissipation</a></h3>
<div class="excerpt">
I am using a 5V regulator (LP2950) from ON Semiconductor. I am using this for USB power and I\'m feeding in 9V from an adapter. USB requires maximum of 500mA right? So the maximum power dissipation in ...
</div>
<div class="tags t-voltage-regulator t-surface-mount t-heatsink t-5v t-power-dissipation">
<a href="/questions/tagged/voltage-regulator" class="post-tag" title="show questions tagged \'voltage-regulator\'" rel="tag">voltage-regulator</a> <a href="/questions/tagged/surface-mount" class="post-tag" title="show questions tagged \'surface-mount\'" rel="tag">surface-mount</a> <a href="/questions/tagged/heatsink" class="post-tag" title="show questions tagged \'heatsink\'" rel="tag">heatsink</a> <a href="/questions/tagged/5v" class="post-tag" title="show questions tagged \'5v\'" rel="tag">5v</a> <a href="/questions/tagged/power-dissipation" class="post-tag" title="show questions tagged \'power-dissipation\'" rel="tag">power-dissipation</a>
</div>
<div class="started fr">
<div class="user-info ">
<div class="user-action-time">
asked <span title="2013-08-27 21:39:31Z" class="relativetime">11 hours ago</span>
</div>
<div class="user-gravatar32">
<a href="/users/10082/david-norman"><div class=""><img src="https://www.gravatar.com/avatar/8b073417e471077280b3fc5ff2eaf1f7?s=32&d=identicon&r=PG" alt="" width="32" height="32"></div></a>
</div>
<div class="user-details">
<a href="/users/10082/david-norman">David Norman</a><br>
<span class="reputation-score" title="reputation score" dir="ltr">322</span><span title="3 silver badges"><span class="badge2"></span><span class="badgecount">3</span></span><span title="10 bronze badges"><span class="badge3"></span><span class="badgecount">10</span></span>
</div>
</div>
</div>
</div>
</div>';
my $regex = qr/(?<code1>id="question-summary-)(?<code2>\d+)/p;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html