Perl Hash of Hashes and Counting

Question

I am trying to process a perl data structure that I have outputted using Data::Dumper

$VAR1 = 'GAHD';
$VAR2 = [
    {   'COUNTRY'       => 'US',
        'NAME'          => 'K. Long',
        'DATE_OF_BIRTH' => '7/27/1957',
        'POSITION'      => 'SENIOR OFFICER',
        'AGE'           => 57,
        'GRADE'         => 'P5'
    },
    {   'COUNTRY'       => 'US',
        'NAME'          => 'J. Buber',
        'DATE_OF_BIRTH' => '12/11/1957',
        'POSITION'      => 'CHIEF',
        'GRADE'         => 'D1'
    },
    {   'COUNTRY'       => 'US',
        'NAME'          => 'M. Amsi',
        'DATE_OF_BIRTH' => '1/1/1957',
        'POSITION'      => 'SENIOR ANIMAL HEALTH OFFICER',
        'AGE'           => 57,
        'GRADE'         => 'P5'
    },
    {   'COUNTRY'       => 'US',
        'NAME'          => 'E. Xenu',
        'DATE_OF_BIRTH' => '8/31/1964',
        'POSITION'      => 'SENIOR OFFICER',
        'AGE'           => 50,
        'GRADE'         => 'P5'
    },
];
$VAR3 = 'GAGD';
$VAR4 = [
    {   'COUNTRY'       => 'US',
        'NAME'          => 'P. Cheru',
        'DATE_OF_BIRTH' => '6/18/1966',
        'POSITION'      => 'ANIMAL PRODUCTION OFFICER',
        'AGE'           => 48,
        'GRADE'         => 'P4'
    },
    {   'COUNTRY'       => 'US',
        'NAME'          => 'B. Burns',
        'DATE_OF_BIRTH' => '2/4/1962',
        'POSITION'      => 'ANIMAL PRODUCTION OFFICER',
        'AGE'           => 52,
        'GRADE'         => 'P4'
    },
    {   'COUNTRY'       => 'US',
        'NAME'          => 'R. Mung',
        'DATE_OF_BIRTH' => '12/13/1968',
        'POSITION'      => 'ANIMAL PRODUCTION OFFICER',
        'AGE'           => 45,
        'GRADE'         => 'P4'
    },
    {   'COUNTRY'       => 'GERMANY',
        'NAME'          => 'B. Scherf',
        'DATE_OF_BIRTH' => '8/31/1964',
        'POSITION'      => 'ANIMAL PRODUCTION OFFICER',
        'AGE'           => 50,
        'GRADE'         => 'P4'
    },
    {   'COUNTRY'       => 'GERMANY',
        'NAME'          => 'I. Hoffmann',
        'DATE_OF_BIRTH' => '2/21/1960',
        'POSITION'      => 'CHIEF',
        'AGE'           => 54,
        'GRADE'         => 'P5'
    },
];

The following is outputted:

1 ADG JUNIOR OFFICER K. King
1 DG SENIOR DIRECTOR K. King
3 P5 SENIOR OFFICER R. Forest
           R.Forest
           K. King
1 P3 JUNIOR OFFICER K. King
3 P1 FORESTRY OFFICER P. Smith
           T. Turner
           K. Turner
1 P1 GENERAL OFFICER K. King

I would like to count the number of GRADES and POSITIONS by Division. Here is the code that I have put together thus far:

#Push data read from a flat file and while loop
push @{ $grades{ $_->{GRADE} }{ $_->{POSITION} } }, $_->{NAME} for @$AG;
for my $key (
    sort { substr( $a, 0, 1 ) cmp substr( $b, 0, 1 ) || substr( $b, 0, 2 ) cmp substr( $a, 0, 2 ) }
    keys %grades
    )
{
    for my $pos ( sort { $a cmp $b } keys %{ $grades{$key} } ) {
        my $names = $grades{$key}->{$pos};
        my $count = scalar @$names;

        print $count, ' ', $key, ' ', $pos, ' ', $names->[0], "\n";
        print '        ', $names->[$_], "\n" for 1 .. $#$names;
    }
}

The code will stop outputting results if duplicate POSITIONS and GRADES data (i.e. P1, Senior Officer) appear in another Division.

I do not know how to access the Hash of Hash by Division (i.e. GAGD, GAGHD,etc.) so that the same GRADEs and POSITIONs will be outputted per division.

Here is what I really need:

**GAGD**
1 ADG JUNIOR OFFICER K. King
1 DG SENIOR DIRECTOR K. King
3 P5 SENIOR OFFICER R. Forest
           R.Forest
           K. King
1 P3 JUNIOR OFFICER K. King
3 P1 FORESTRY OFFICER P. Smith
           T. Turner
           K. Turner
1 P1 GENERAL OFFICER K. King

**GAGHD**
1 P3 JUNIOR OFFICER P. Green
3 P1 FORESTRY OFFICER R. Brown
           F. Boo
           K. Church
1 P1 GENERAL OFFICER D. Peefer

etc.
etc.

Answer 1

It seems you want to hash the information by Division, then count and store names by grade + position. The following seems to work for me:

#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

my %grades = (
    GAHD => [ {
               NAME => 'K. Long',
               POSITION => 'SENIOR OFFICER',
               GRADE => 'P5'
              },
              {
               NAME => 'J. Buber',
               POSITION => 'CHIEF',
               GRADE => 'D1'
              },
              {
               NAME => 'M. Amsi',
               POSITION => 'SENIOR ANIMAL HEALTH OFFICER',
               GRADE => 'P5'
              },
              {
               NAME => 'E. Xenu',
               POSITION => 'SENIOR OFFICER',
               GRADE => 'P5'
              },
            ],
    GAGD => [
             {
              NAME => 'P. Cheru',
              POSITION => 'ANIMAL PRODUCTION OFFICER',
              GRADE => 'P4'
             },
             {
              NAME => 'B. Burns',
              POSITION => 'ANIMAL PRODUCTION OFFICER',
              GRADE => 'P4'
             },
             {
              NAME => 'R. Mung',
              POSITION => 'ANIMAL PRODUCTION OFFICER',
              GRADE => 'P4'
             },
             {
              NAME => 'B. Scherf',
              POSITION => 'ANIMAL PRODUCTION OFFICER',
              GRADE => 'P4'
             },
             {
              NAME => 'I. Hoffmann',
              POSITION => 'CHIEF',
              GRADE => 'P5'
             },
            ]);

for my $division (keys %grades) {
    say "**$division**";
    my %group;
    for my $person (@{ $grades{$division} }) {
        my $position = join ' ', @{ $person }{qw{GRADE POSITION}};
        push @{ $group{$position} }, $person->{NAME};
    }

    for my $position (keys %group) {
        say join ' ', scalar @{ $group{$position} },
                      $position,
                      $group{$position}[0];
        my @remaining_names = @{ $group{$position} };
        shift @remaining_names;
        say "\t$_" for @remaining_names;
    }
    say q();
}

Update

If you store more information than a name for a person in an array ref (push push @{ $group{$position} }, [ ... ];), you can then retrieve it by dereferencing each reference, for example in map:

    say join ' ', scalar @{ $group{$position} },
                  $position,
                  join "\n\t", map "@$_", @{ $group{$position} };

Answer 2

You're almost there with the code that you've got. Assuming that the hash you've printed out is called %grades, I would do the following:

foreach my $g (sort keys %$grades) {
    print "**$g**\n";
    # put the info to be printed in a temporary hash
    my %temp;
    foreach (@{$grades->{$g}}) {
        push @{$temp{ $_->{GRADE}." ".$_->{POSITION} }}, $_->{NAME};
    }
    foreach (sort keys %temp) {
        # print a count of the number of names, then the grade/position info
        print scalar @{$temp{$_}} . " $_ "
        # @{$temp{$_}} holds the names, so just sort them and print them out.
        . join("\n\t\t\t", sort @{$temp{$_}}) . "\n";
    }
}