in reply to Grabbing part of an HTML page

Why not just use one regular expression? 
#!/usr/bin/perl
use strict;

my $start_pattern = '<!-- start section-->';
my $end_pattern = '<!-- end section -->';
my @files_to_look_in = ("/path/to/files1.html", "/path/to/files2.html"
+);

for(@files_to_look_in) {
    local $/;
    open(HTM_FILE, <$_) || die "Can't open file: $!";
    my $file = <HTM_FILE>;
    if ($file =~ /$start_pattern(.*)$end_pattern/s) {
        print "$1";
    }
}

[download]

Note: If I hadn't localized $/ (the input record seperator), I would have needed to add a /s modifier to the regular expression to match on the whole file.

cLive ;-)

update: oops, not paying attention "while" is now "for". 2) made a boo-boo - see below...

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Re: Re: Grabbing part of an HTML page
by graff (Chancellor) on Mar 29, 2004 at 01:53 UTC
    For the single regex to work, you would need to add the "s" modifier at the end, so that your ".*" doesn't stop matching at the first line-break character. Also, depending on the nature of the OP's data, it may need to be a non-greedy match: 
       # ...
   if ( $file =~ /$start_pattern(.*?)$end_pattern/s ) {
      print $1;
   }
   # ...

    [download]
    update: Forgot to mention: if the OP's data happens to contain more than one "start ... end" sequence within the same file, this would have to be structured as a loop -- something like: 
       #
   while ( $file =~ /start_pattern(.*?)$end_pattern/gs ) {
      print "$1\n";
   }
   #

    [download]
[reply]
[d/l]
[select]

      What does the /s modifier do if $/ is undefined? :)

      cLive ;-)

[reply]
        Well, the current value of $/ has nothing to do with whether or not "." in a regex will match "\n" in a given string value; only the "s" modifier on the regex will allow "." to match "\n", no matter what $/ is. Try this out: 
        #!/usr/bin/perl

$/ = undef;
$_ = <DATA>;

while ( /begin(.*?)end/g ) {
   print "\n--- found without 's': ---\n$1\n";
}
while ( /begin(.*?)end/gs ) {
   print "\n--- found using 's': ---\n$1\n";
}

__DATA__
blah
begin 
foo
bar
baz
end
begin foo2
bar2
baz2
end

        [download]
[reply]
[d/l]
Re: Re: Grabbing part of an HTML page
by pbeckingham (Parson) on Mar 28, 2004 at 22:30 UTC

    You have written another infinite loop - the while (@files_to_look_in) is always true, and no part of the code shifts or pops values from the array.

[reply]
[d/l]

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