my %foo;
@foo{qw/ foo bar baz /} = 1 .. 3;
while (%foo) {
    my $key = each %val;
    my $val = delete $foo{$key};
    printf "%s => %s is gone.\n", $key, $val;
}

##</code><code>##

my %foo;
@foo{qw/ foo bar baz /} = 1 .. 3;
my @keys = keys %foo; 
while (%foo) {
    my $key = shift @keys;
    my $val = delete $foo{$key};
    printf "%s => %s is gone.\n", $key, $val;
}

##</code><code>##

while (my ($key, $val) = each %hash) {
    delete $hash{$key};
    printf "%s => %s is gone.\n", $key, $val;
}