I would copy @Single and @Double into hashes. Use exists rather than grep. 
use strict;
use warnings;
my @choices = qw/Apple Banana Tiger Lion Cat Turtle/;
my @Single = qw/Apple Turtle/;
my @Double = qw/Lion/;
my %Single_hash = map {$_ => 1} @Single;
my %Double_hash = map {$_ => 1} @Double;
foreach my $choice (@choices) {
    my $flag
        = exists $Single_hash{$choice} ? 1
        : exists $Double_hash{$choice} ? 2
        :                                0
        ;
    print "$choice => $flag\n";
}

[download]
Bill

In reply to Re: The most efficient way for searching for an element in an array? by BillKSmith
in thread The most efficient way for searching for an element in an array? by Ppeoc

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