References are a big spicy meatball! And, of course, there's more than one way to do it.

The following snippet might help:

use strict;

my %packet_fields = (
  'Format_X' => ['ident', 'flags', 'x', 'y', 'mode3'],
  'Format_Y' => ['ident', 'RDP_Ident', 'Radar_Site_Ident', 'site_x']
);

foreach my $format (keys %packet_fields) {
  foreach my $field (@{$packet_fields{$format}}) {    #line 9
    print "$format -> $field\n";
  }
}

foreach my $format (keys %packet_fields) {
  print "$format's 2nd field = ", $packet_fields{$format}->[1], "\n"; 
+#line 15
  print "$format's 3rd field = ", $packet_fields{$format}[2], "\n"; #l
+ine 16
}

[download]

In this sample, %packet_fields is a regular old hash. The keys for this hash are garden-variety scalars. The value associated w/ each key is a reference to an anonymous (unnamed) array. These two anon. arrays are the only references that we have to deal with, and the only things that require any dereferencing syntax.

The @{} in line 9 is using a form of dereferencing notation to give me an array.

There's another form of dereferencing that I can use, too, as seen in lines 15 and 16.

Hanlon's Razor - "Never attribute to malice that which can be adequately explained by stupidity"

In reply to Re: Help with hash/array data structure by Art_XIV
in thread Help with hash/array data structure by robinbowes

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