Re: Retrieve unique values from Hash of Hashes

my %seen;
my $num_unique_users =
    grep !$seen{ $HoH{$_}{user} }++,
    keys(%HOH);
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If you actually want the name of the users:

my %seen;
my @unique_users =
    grep !$seen{ $HoH{$_}{user} }++,
    keys(%HOH);
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my %seen;
my @unique_users =
    grep !$seen{$_}++,
    map $HoH{$_}{user},
    keys(%HOH);
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Comment on Re: Retrieve unique values from Hash of Hashes Select or Download Code

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Re^2: Retrieve unique values from Hash of Hashes by 7stud (Deacon) on Nov 09, 2009 at 23:04 UTC
Oh, man. That's tight. Here's a beginner's version: `use strict; use warnings; use 5.010; my %HoH = ( '192.168.0.1' => { user => "fred", pass => "barney", }, '192.168.0.2' => { user => "george", pass => "tester", }, '192.168.0.3' => { user => "homer", pass => "abc123", }, '192.168.0.6' => { user => "fred", pass => "barney", }, ); my %unique; foreach my $key (keys %HoH) { my $user = $HoH{$key}->{'user'}; $unique{$user} = 1; } my $count = keys %unique; say $count; --output:-- 3` [download]	[reply] [d/l]

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Re^2: Retrieve unique values from Hash of Hashes
by 7stud (Deacon) on Nov 09, 2009 at 23:04 UTC

Oh, man. That's tight.

Here's a beginner's version:

use strict;
use warnings;
use 5.010;

my %HoH = (
    '192.168.0.1' => {
        user   => "fred",
        pass   => "barney",
    },
    '192.168.0.2' => {
    user   => "george",
        pass   => "tester",
    },
    '192.168.0.3' => {
        user   => "homer",
        pass   => "abc123",
    },
    '192.168.0.6' => {
        user   => "fred",
        pass   => "barney",
    },
);

my %unique;

foreach my $key (keys %HoH) {
    my $user = $HoH{$key}->{'user'};
    $unique{$user} = 1;
}

my $count = keys %unique;
say $count;

--output:--
3
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