my %countries = (
    India    => 1,
    America  => 1,
    Germany  => 1,
    Austria  => 1,
);

if ($countries{$country}){
   print "$country is indeed a country\n";
}

##</code><code>##

use v6; # ensure we run Perl 6
my $country = 'Foo'
if $country eq 'America' | 'India' | ... {
    say "True"
}

# or if you want to use an array:
my @countries = <America India Germany Austria>;
if $country eq any(@countries) {
   say "True"
}

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;

# get list of countries:

open my $f, '<:encoding(UTF-8)', 'countries'
    or die "Can't read file: $!";
my @countries = <$f>;
close $f;
chomp @countries;
for (@countries) {
    s/^([^;]+).*/\u\L$1/;
}

use Benchmark qw(cmpthese);
use List::Util qw(first);

my $re = join '|', map quotemeta, @countries;
sub regex {
    die "regex" unless 'Germany' =~ m/^(?:$re)$/;
    die "regex" if '    Foo'     =~ m/^(?:$re)$/;
}

sub mgrep {
    die "grep" unless grep { $_ eq 'Germany' } @countries;
    die "grep" if     grep { $_ eq 'Foo' }     @countries;
}

sub mfirst {
    die "grep" unless first { $_ eq 'Germany' } @countries;
    die "grep" if     first { $_ eq 'Foo' }     @countries;
}

my %hash = map { $_ => 1 } @countries;
sub hash {
    die "hash" unless $hash{Germany};
    die "hash" if     $hash{Foo};
}


cmpthese(-1, {
    regex   => \&regex,
    grep    => \&mgrep,
    first   => \&mfirst,
    hash    => \&hash,
});

##</code><code>##

# perl 5.8.8:
           Rate   grep  first  regex   hash
grep     8219/s     --   -17%   -72%  -100%
first    9863/s    20%     --   -67%  -100%
regex   29805/s   263%   202%     --   -99%
hash  3682290/s 44701% 37233% 12255%     --

# perl 5.10.0:
           Rate   grep  first  regex   hash
grep     8532/s     --   -21%   -80%  -100%
first   10778/s    26%     --   -75%  -100%
regex   43115/s   405%   300%     --   -99%
hash  3429921/s 40099% 31723%  7855%     --

##</code><code>##

sub smartmatch {
    die 'smart' unless 'Germany' ~~ @countries;
    die 'smart' if     'Foo'     ~~ @countries;

}
__END__
           Rate   grep  first  smart  regex   hash
grep     7587/s     --   -17%   -58%   -83%  -100%
first    9135/s    20%     --   -50%   -79%  -100%
smart   18101/s   139%    98%     --   -59%   -99%
regex   43840/s   478%   380%   142%     --   -99%
hash  3508785/s 46146% 38312% 19285%  7904%     --