my @list= <DATA>;
@list= @list[
    map { unpack "N", substr($_,-4) }
    sort
    map {

        # Only these two lines had to be written:
        my( $foo, $bar )= $list[$_] =~ / (\d+) /g;
        ~pack("N",$bar) . pack("N",$foo)

          . pack "N", $_
    } 0..$#list
];
print @list;
__END__
Item1 - 2 foo, 2 bar
Item2 - 0 foo, 1 bar
Item3 - 1 foo, 3 bar
Item4 - 1 foo, 2 bar
Item4 - 3 foo, 2 bar
Item4 - 0 foo, 2 bar