Deb <[EMAIL PROTECTED]> writes:
>
> I understand this:
>
> foreach $listname (sort keys %Lists) {
> print "$listname\n";
> }
>
> But, I don't quite get how to get to the key values
> below that. I know I'm so close, but just not quite
> there...
>
> Could some kind soul give me a blow by blow "what's
> happening here" going from
>
> $Lists{$listname} = \%hrLists;
>
> to printing out the key, values by $listname?
>
Don't mean to thump the FM, but have you seen the
"Access and Printing of a HASH OF HASHES" section
in perldsc? Your %Lists is a perfect %HoH.
But anyway, as you've probably seen, the ordinary
"print a hash" loop...
for my $key (sort keys %Lists) {
print "$key => $Lists{$key}\n";
}
Produces something like this.
list-1 => HASH(0x80fb32c)
Where "HASH(0x80fb32c)" represents the hash reference.
you created way... back.. here:
$Lists{$listname} = \%hrLists;
# ^
# backslash creates a reference
#
So what you've got is a nested data structure; a
hash (%List) whose values are references to more
hashes.
To print it out, you just need two loops, an outer
loop for %Lists, and an inner loop to iterate over
the nested hashes.
for my $list (sort keys %Lists) {
print "$list: \n";
my $ref = $Lists{$list};
#
# use "%{$ref}" to dereference
#
for my $key (sort keys %{$ref}) {
print " $key : $ref->{$key}\n";
}
}
And besides perldsc, you might find these handy if
you're learning/working-with references:
$ perldoc perlreftut
$ perldoc perlref
--
Steve
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