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At 11:02 AM -0700 9/4/09, Noah Garrett Wallach wrote:
>Hi there,
>
>I am having some trouble understanding hash of hashes here. I want
>to find all the keys for %policy{'policy_statement'}
>
> for my $line (@lines) {
> for my $key ( keys %policy{'policy_statement'} ) {
%policy is a hash.
$policy{policy_statement} (quotes not needed in this case) is a
scalar value of the element with key 'policy_statement'. The scalar
value is a reference to a hash.
Therefore, %{$policy{policy_statement}} is the hash to which this
value refers. You can occasionally leave out the outer set of braces,
but not in this case.
So change the above to
for my $key ( keys %{$policy{'policy_statement'}} ) {
Elements of the second-level hash and deeper hashes may be referred
to with the following:
$policy{key1}->{key2}
$policy{key1}->{key2}->{key3}
etc. In this case you may leave out the -> symbols.
> if ($line =~
>/set\sprotocols\sbgp\sgroup\s(\S+)\s(import|export).*?$key\s/) {
> $policy{'policy_statement'}{$key} = 2;
> $policy{'policy_statement'}{$key}{'group_name'}{$1} = 1;
> $policy{'policy_statement'}{$key}{'policy_type'}{$2} = 1;
The rest looks OK, and compiles.
--
Jim Gibson
Jim@Gibson.org
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