use strict;
my $str = '# This is a comment <-beacuse it starts at the begining of the file
# This is a comment <- see above
# 1. Item one <- not a comment because it starts with 1.
# Description of Item 1 <- not a comment as it is after a line that starts with a number
data point 1
data point 2
data point etc
3 <-- represents number of data points under Item one
# 2. Item two <-- not a comment
# Description of item 2 <-- not a comment
data point 1
data point ..
data point 100
100
#3. Item three <--- not a comment
# Item three description
0';
my $regex = qr/^(?=\# ?\d+\.)/mp;
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