Perl Regex for Not HTML - html

Question

I am looking to substitute anything that is not an HTML tag from an HTML document. So, basically trying to get rid of all the text within the document.
I have the below regex to remove all HTML from a string, but need help with the opposite scenario.
$string =~ s/<[^>]+>//g;
Thanks.

Answer 1

If this is regex s///ubstitution to remove all html from document
$string =~ s/<[^>]+>//g;
Then you can use the same regex in a m//atch operator to keep all html from document
$string = join '', $string =~ m/<[^>]+>/g;
If the above regex satisfies your requirements, then you're done :) But maybe you want to consider this ol' regex pattern, slightly longer :D http://perlmonks.org/?node_id=161281
Mind the caveats like Ethan Browne mentions :)

Answer 2

Ethan Brown namechecks HTML::DOM as if it were the only CPAN solution.
HTML::Parser is more ubiquitous, but it's not hard to Google for more.
http://metacpan.org/pod/HTML::Parser
A solution using HTML::Parser is (tested once):
use HTML::Parser ();
my $p = HTML::Parser->new(api_version => 3);
$p->handler( text => sub { }, "");
$p->handler( default => sub { print shift }, "text");
$p->parse_file('content.html') || die $!;

Answer 3

Are you looking for this?
$string =~ s/>[^<]*</></mg;
Or this?
$string =~ s/(?<=>)[^<]*(?=<)//mg;

Answer 4

LibXML makes it easy to select stuff that isn't tags/comments/processing-instruction and remove it
#!/usr/bin/perl --
use strict;
use warnings;
use XML::LibXML 1.70; ## for load_html/load_xml/location
use XML::LibXML::PrettyPrint;
Main( #ARGV );
exit( 0 );
sub Main {
binmode STDOUT;
my $loc = shift or die "
Usage:
$0 ko00010.html
$0 http://example.com/ko00010.html\n\n";
my $dom = XML::LibXML->new(
qw/
recover 2
no_blanks 1
/
)->load_html( location => $loc, );
## http://www.w3.org/TR/xpath/#node-tests
## http://www.w3.org/TR/xpath/#NT-NodeType
## http://www.w3.org/TR/xpath/#section-Text-Nodes
for my $text ( $dom->findnodes(q{ //text() }) ){
node_detach( $text );
}
local $XML::LibXML::skipXMLDeclaration = 1; ## <?xml ?>
local $XML::LibXML::setTagCompression = 0; ## <p />
#~ print "$dom";
my $pp = XML::LibXML::PrettyPrint->new_for_html;
$pp->{indent_string}=' ';
print $pp->pretty_print( $dom );
}
sub node_detach {
my( $self ) = #_;
$self->parentNode->removeChild( $self );
}