Find regexp matches starting from specific position in Perl

Question

I have 2 RegExps. How can I get the start position of first RegExp matched substring and start to find second RegExp matching from this position?

UPD: For example:

$_ = "
=cut
vffdv
vdfvfd
vdfvfdvfd
=pod
dvfddv
vfdvfdvf
vdfvfdvfd
=end
";
$\ = "\n";

sub get {
 my $_ = shift;
 /=((\d|\w)+)/i;
 return $1;
}


print get($_) while /^=/mg;

Prints

cut
cut
cut

But I need

cut
pod
end

@HamZa But there will be list of `=`. And RegExp from `get` won't work. — michaeluskov, Dec 20 '13 at 09:04

mpapec · Accepted Answer · 2013-12-20T09:32:44.853

3

You're sending $_ which doesn't change in while loop and it is defined at start of the script to get() function.

You need to capture content and send $1 to function.

print get($1) while /^=(.+)/mg;

Side note; most of the time do prefer named variables over implicit $_. Also my $_ = .. is asking for trouble if you're expecting dynamic scoping for $_ global, and lexical $_ is clobbering it.

edited Dec 20 '13 at 09:32

answered Dec 20 '13 at 09:21

mpapec

50,217
8
67
127

score 1 · Answer 2 · answered Dec 20 '13 at 13:41

1

you can use something like this

$_ = "
=cut
vffdv
vdfvfd
vdfvfdvfd
=pod
dvfddv
vfdvfdvf
vdfvfdvfd
=end
";

my @array = split /\n/ , $_;
for ( @array ){
    if( $_ =~ /^=/ ){
        print substr( $_ , 1 ) . "\n";
    }
}

answered Dec 20 '13 at 13:41

brianadams

233
1
5

score 0 · Answer 3 · answered Dec 20 '13 at 17:35

0

This works like I need.

$_ = "
=cut
vffdv
vdfvfd
vdfvfdvfd
=pod
dvfddv
vfdvfdvf
vdfvfdvfd
=fuck
";
$\ = "\n";

sub get {
 my $_ = shift;
 my $start = shift;
 pos($_) = $start - 1;
 /=((\d|\w)+)/ig;
 return $1;
}


print get($_,pos $_) while /^=/mg;

answered Dec 20 '13 at 17:35

michaeluskov

1,729
7
27
53

Find regexp matches starting from specific position in Perl

3 Answers3