my @arr = grep {/\[tab\]/ and s/^<p>//} split /<\/p>/, $contents;

##</code><code>##

my @arr = grep /\[tab\]/, split /(?<=<\/p>)/, $contents;

##</code><code>##

{
  local $/ = '</p>';
  open (STR, '<', \$contents) or die "Opening string: $!\n";
  @arr = grep /^<p>/ && /\[tab\]/, <STR>;
  print "read $_\n" for @arr;
}