Question

I dropped the idea of using this for my program, but I am intrigued because I never found the answer to how to do this. Basically, if I construct something like the following (Please forgive my formatting if the following doesn’t appear okay):

• A = |num_key => hashref_a|,
• hashref_a is a hash reference to a = |string_keys => hashref_b|,
• hashref_b is a hash reference to b = |num_key, num_value|.

So as you see, the first level is a hash with keys being numbers and its values are references to another hash, which in turn is a hash whose keys are strings related to values which are again hash references (these are however hashes of just keys and numbers).

Now, how do I access b (the entire list of keys or just the value for a corresponding key) given a num_key for the first hash and a particular string_key for the second hash.

I really hope I was able to communicate the question clearly!

Answer 1

If I’ve understood your request correctly:

my %hash = ( num_key => { string_keys => { num_key => 1.234 } } );

Or:

my %hash_b = ( num_key => 1.234 );
my %hash_a = ( string_keys => \%hash_b );
my %hash_z = ( num_keys => \%hash_a );

Hmmm…after editing the question, I think you’re asking how to access the values, rather than how to construct them.

my $value = $hash{$num_key}->{$string_key}->{num_key};

It gets a bit iffy here; I’ve used $num_key but the only valid value for that given the data is ‘num_key’; similarly with $string_key and ‘string_keys’. The arrows are the key to the notation, though.