However be careful with exists(), it creates stuff for you:

use Data::Dumper;

use strict;
use warnings;

my $h = {};
if (exists($h->{"a"}{"b"})) {
}
if (exists($h->{"a"})) {
    print "exists\n";
}
print Dumper($h);
[download]

This will make $h->{"a"} exists.

Yes, do beware autovivification.

HTH,

planetscape

print "From outside the subroutine:\n";
my $i = 0;
while ( $i < @names )
{
    print "$myHash{ $names[$i] }{ name }\n";
      $i++;
}
[download]

Use of uninitialized value in concatenation (.) or string at hashOfHas
+hes.pl line 22, <INFO> line 5.
[download]

Personal preference, but I would write it like:

foreach my $key (@names) {
    print $myHash{$key}{'name'}, "\n";
}
[download]

Of course, that would mean that at some point you would have had to assign a hash value with the key 'name' to each nested hash.

Hey hubb0r,

Sure appreciate the assistance, but I don't think this one works. I'll supply the code. It just keeps failing for the same reason:

Use of initialized value in print at hashOfHashes.pl line 22, <INFO> line 6.

Here's the code and Line 22 is the print statement(by the way, the key values successfully print out):



#!/usr/bin/perl -w

use strict;

my %myHash = ();
my @names;

open (INFO,"<info.txt");

while (<INFO>)
{
    my ($name,$species,$gender,$age,$hairColor) = split /,/,$_;
    push @names,$name;
    $myHash{ $name } = {};
    addValues( $myHash{ $name },\$name,\$species,\$gender,\$age,\$hair
+Color);
}

print "From outside the subroutine:\n";
foreach my $key ( @names )
{
    print "Key:\t$key\n";
    print $myHash{$key}{'name'}, "\n";
}

close (INFO);

sub addValues
{
    my ( $hashNameRef,$namRef,$speRef,$genRef,$ageRef,$hairColRef ) = 
+@_;
    
    $hashNameRef = { 
        name        => $$namRef,
        species        => $$speRef,
        gender        => $$genRef,
        age        => $$ageRef,
        hairColor    => $$hairColRef
    };
    print "$$hashNameRef{'name'}\t$$hashNameRef{'species'}\t$$hashName
+Ref{'gender'}\t$$hashNameRef{'age'}\t$$hashNameRef{'hairColor'}\n";
}
[download]

And again, here is the data file:



Tony,human,male,47,gray
Mark,human,male,48,brown
Tyler,dog,male,11,brown
Anthi,human,female,39,black
Spud,cat,male,14,white
Erica,human,female,23,blonde
[download]

Am I doing something wrong? I don't know, man! I tried a lot of syntax variants, but no go. I always get that error message.

Tony (o2bwise)