use strict ;
use warnings ;
use Data::Dumper ;

open my $dataIn1, "<", "ID_file.txt" or die "NO ID FILE: $!";
open my $dataIn2, "<", "Attribute_file.txt" or die "NO ATTR FILE: $!";

my $data = () ;
my $attrs = () ;

sub getdata {
    my ( $fileName, $type ) = split /\t/, $_[1] ;
    push @{$data}, $type unless !defined $fileName ;
}

sub getattrs {
    my @attrs = split /\t/, $_[1] ;
    shift @attrs ;
    push @{$attrs}, \@attrs unless !defined $attrs[0] ;
}

while( <$dataIn1> ) {
	chomp ;
	# In my previous example I used
	# a counter which is not available
	# here, so that is why the first
	# value is 0
	getdata( 0, $_ ) ;
}

while( <$dataIn2> ) {
	chomp ;
	getattrs( 0, $_ ) ;
}

print Dumper( $data ) ;
print Dumper ( $attrs  ) ;