Perl Hashes

my %hash = ( # create hash
    name => "John",
    age => 30
);
my %ages = ("Alice", 25, "Bob", 30); # list form

$hash{name} # access value by key
$hash{city} = "NYC"; # add/update key-value
delete $hash{age}; # remove key

keys(%hash) # get all keys
values(%hash) # get all values
exists($hash{name}) # check if key exists
defined($hash{name}) # check if value defined

foreach my $key (keys %hash) { # iterate keys
    print "$key: $hash{$key}\n";
}
while ((my $key, my $value) = each %hash) { # iterate pairs
    print "$key: $value\n";
}