I can think of 3 ways: 
use warnings;
use strict;
use List::MoreUtils qw (any);

my $var = 3;

if (grep { $var == $_ } 2, 3) {
    print "in list\n";
}
else {
    print "not in list\n";
}

if (any { $var == $_ } 2, 3) {
    print "in list\n";
}
else {
    print "not in list\n";
}

my %vals = map {$_ => 1} 2, 3;
if (exists $vals{$var}) {
    print "in list\n";
}
else {
    print "not in list\n";
}

__END__

in list
in list
in list

[download]
Update: a 4th way involves the smart match operator 
use 5.010;
if ($var ~~ [2, 3]) {
    print "in list\n";
}
else {
    print "not in list\n";
}

[download]

In reply to Re: comparison with bitwise operators by toolic
in thread comparison with bitwise operators by alextor

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