# Method 1
push @data, {%tmp};

# Method 2
push @data, \%tmp;

##</code><code>##

sub read_dat
{
    my $file = shift;
    my @data = ();
    
    while ( defined (my $line = <DATA>) ) {
        next unless $line =~ m/\w+/;
        chomp $line;
        my @line = split (",", $line);

        my %tmp = map {
           $columns[$_] => $line[$_]
        } 0..$#columns;
        
        push @data, \%tmp;
    
    }
    return @data;
}