To use your data structures, you can do this:

#create list of hashes
my @allhashes = ( \%hash1, \%hash2, \%hash3 );

#note the following assumes all keys exist and are the same
#keys are not sorted in this example
foreach my $key (keys %hash1) {
    print "key $key\n";
    foreach my $hash (@allhashes) {
        print "Value: $hash->{$key}\n";
    }
}
[download]

Re-Update: Deleted a bunch of stuff that I thought was relevant, but wasn't.

You can convert your data via something like:

    my $devs= hashjoin( {
        version=>\%vers, module=>\%mod, memory=>\%mem } );

sub hashjoin {
    my( $in )= @_;
    my $out= {};
    for my $attrib (  keys %$in  ) {
        for my $item (  keys %{ $in->{$attrib} }  ) {
            $out->{$item}->{$attrib}= $in->{$attrib}->{$item};
        }
    }
    return $out;
}
[download]

Here is yet another case where I really want my "dereference an entire list at a time" operators. Then I could replace that middle loop with:

    $out->@{ keys $in->{$attrib}->% }-->{$attrib}=
        values $in->{$attrib}->%;
[download]

I'd love to see an elegant method for generating the data in the format that merlyn suggested from the beginning, if each attribute is gathered from a different subroutine.

@keys = ("key1","key2,"key3","key4");
foreach $key (@keys) {
    print "$key\n";
    print "$hash1{$key} , \$hash1\n";
    print "$hash2{$key} , \$hash2\n";
    print "$hash3{$key} , \$hash3\n";
    print "$hash4{$key} , \$hash4\n\n";
}
[download]

- p u n k k i d
"Reality is merely an illusion, albeit a very persistent one." -Albert Einstein

All the keys in each hash are the same so couldn't you do the following:

foreach (keys %hash1) {
   ...  # here you would use $_ as the variable for the keys
}
[download]

This eliminates the creation of the @keys and $key variables. Hope that helps.

Zenon Zabinski | zdog | zdog7@hotmail.com

%hash 1
keys = device names
values = software version

%hash 2
keys = device names
values = "module 1\n module 2 \n......."

%hash 3
keys = device names
values = either "$pub" or "$prv", depending upon device

%hash 4 
keys = device names
values = amount of memory
[download]

"device name"
"==========="
"software version"
"module 1"
"module 2"
"module 3....."
"public": ($pub, if defined)
"private": ($prv if defined)
"amount of memory"
[download]

Restructure your data so you have:

%device_info = (
  device1 => { version => '1.4', module => [1, 2, 3], memory => '18k' 
+},
  device2 => { version => '1.4', module => [4,5,6], memory => '25k' },
  device3 => { version => '1.2', module => [7,8,9], memory => '18k' },
);
[download]

Then it's easy to do operations in parallel. Having upside-down data structures is nasty.

-- Randal L. Schwartz, Perl hacker

The code I posted above should print this out (with some cosmetic work to the print statements, and some "if exists" statements). You really should look into making this a structure like the one merlyn posted though.

Give it a shot, and reply with any errors you get.

As I am relatively new to Perl, I have no idea what merlyn was talking about.

-- Randal L. Schwartz, Perl hacker