my $string = "";
my @new_array;
for my $item (@contigfile) {
     if ( $item =~ /^>\d) {
          push @new_array, $string unless $string eq "";
          $string = "";
     } else {
          $string .= $item;
     }
}
push @new_array, $string; # takes care of the last element

##</code><code>##

my $string = "";
while (my $line = <$input_fh>) {
     chomp $line;
     if ( $line =~ /^>\d) {
          push @new_array, $string unless $string eq "";;
          $string = "";
     } else {
          $string .= $line;
     }
}     
push @new_array, $string; # take care of the last element