use strict;
my $str = 'Hello world!
<a href="https://www.youtube.com/watch?v=m7t75u72vd">ABC</a>
Blah blah blah...
https://www.youtube.com/watch?v=df82vnx07s
Blah blah blah...
<p>https://www.youtube.com/watch?v=nvs70fh17f3fg</p>';
my $regex = qr/[a-zA-Z\/\/:\.]*youtu(?:be\.com\/watch\?v=|\.be\/)([a-zA-Z0-9\-_]+)(?![^<]*>)/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