my %month_hash = (
    '1' => 'January',
    '2' => 'February',
    '3' => 'March',
    '4' => 'April'
);

##</code><code>##

my @order = (1 .. 4);

##</code><code>##

my @months = @month_hash{@order};
print $_,$/ for @months;

##</code><code>##

delete $month_hash{3};
my @months = @month_hash{@order};
print $_,$/ for @months;