身份証號 -> 姓名
單字出現次數

my %family_name;

$family_name{'fred'}   = 'flintstone';
$family_name{'barney'} = 'rubble';

foreach my $person (qw /barney fred/){
 print "我聽過 $person $family_name{$person}. \n";
}

my %hash1 =('Jack', 'Chue', 'Danel', 'Eng');

my %hash2 = (
 'foo'  => 35,
 'bar'  => 12.4,
 2.5    => 'hello');


my %hash3 = (
 foo    => 35,
 bar    => 12.4,
 2.5    => 'hello');

foreach (keys %hash3){
 print "$_ $hash{$_}\n";
}

my %h=('a' => 1, 'b' => 2, 'c' => 3);

while (my ($k, $v) = each %h){
 print "$k $v\n";
}

if (exists $h{'d'}){
 print "there is d\n";
}
else {
 print "no d\n";
}