@foo = (0,1);
$hash{00} = "data";
$hash{10} = "moredata";

print '$hash{00} is ', $hash{00} , "\n";
print '$hash{$foo[0] . "0"} is ', $hash{$foo[0] . "0"}, "\n";
print '$hash{$foo[1] . "0"} is ', $hash{$foo[1] . "0"}, "\n";
print '$hash{10} is ', $hash{10} , "\n";

##</code><code>##

$hash{00} is data
$hash{$foo[0] . "0"} is 
$hash{$foo[1] . "0"} is moredata
$hash{10} is moredata