moritz explained, so what follows is a solution. Basically, comparing a single value against an array makes so sense. By using grep, the value can be compared against every element of the array. 

#!/usr/bin/perl

use strict;
use warnings;

my %hoa = (
   arraya => [qw( dd1 dd2 dd3 dd4 )],
   arrayb => [qw( gg1 gg2 gg3 gg4 )],
   arrayc => [qw( cc1 cc2 cc3 cc4 )],
);

chomp( my $array_name = <STDIN> );   # e.g. arraya 
chomp( my $to_find    = <STDIN> );   # e.g. dd2

if (  exists( $hoa{$array_name} )
   && grep { $_ eq $to_find } @{$hoa{$array_name}}
) {
   print( @{$hoa{$array_name}}, "\n" );
}

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In reply to Re^2: specific array in hash of arrays by ikegami
in thread specific array in hash of arrays by kwn

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