use 5.010;

my @set = qw/banana plum apple strawberry pear/;

my $var = "apple";
if ($var ~~ @set) {
	say "yes";
}

##</code><code>##

my %set = map { $_ => 1 } qw/banana plum apple strawberry pear/;
if (exists $set{$var}) {
	say "yes";
}