Accessing hash of hashes defined in another file in perl and printing it

Question

Now my file1 contains the hash of hashes as shown below:

package file1;

our %hash = (
    'articles' =>  {
                       'vim' => '20 awesome articles posted',
                       'awk' => '9 awesome articles posted',
                       'sed' => '10 awesome articles posted'
                   },
    'ebooks'   =>  {
                       'linux 101'    => 'Practical Examples to Build a Strong Foundation in Linux',
                       'nagios core'  => 'Monitor Everything, Be Proactive, and Sleep Well'
                   }
);

And my file2.pl contains

#!/usr/bin/perl
use strict;
use warnings;

require 'file1';

my $key;
my $key1;

for $key (keys %file1::hash){
   print "$key\n";

   for $key1 (keys %{$file1::hash{$key1}}){
   print "$key1\n";
   }
}

Now my question is, I get an error

"Use of uninitialized value in hash element at file2.pl"

when I try to access the hash like this:

for $key1 (keys %{$file1::hash{$key1}})

Kindly help.

Answer 1

It's because $key1 is not defined.

You meant to use %{ $file1::hash{$key} } instead.

---

Note that if you avoid pre-declaring $key1, the strict pragma can catch it at compile-time:

for my $key (keys %file1::hash){

   print "$key\n";

   for my $key1 (keys %{$file1::hash{$key1}}){
       print "$key1\n";
   }
}

Message

Global symbol "$key1" requires explicit package name