Perl - 有序多维散列（使用 Hash::Ordered）答案

【问题标题】：Perl - Ordered multi-dimensional hash (use Hash::Ordered)Perl - 有序多维散列（使用 Hash::Ordered）
【发布时间】：2021-07-11 12:18:26
【问题描述】：

我正在尝试按照我创建它的确切顺序遍历 Perl 中的多维哈希。我正在使用 Hash::Ordered，但无法让它工作。

如果我使用 Data::Dumper 打印 $MENU_ITEMS，我会看到我期望的哈希元素（见下文），但是，当我尝试将它们摄取到 $ITEM 中时，它是空白的。

我确定我在做一些愚蠢的事情，请帮助:)

use Hash::Ordered;
$MENU_SECTIONS = Hash::Ordered->new
    (
    'MENU_manage_properties' => 
        {
        'show_current_properties'  => 'Current Properties',
        'show_prospect_properties' => 'Prospect Properties'
        },
    'MENU_reports' => 
        {
        'some_report'             => 'Some report',
        'another_report'          => 'Another report'
        },
    'MENU_settings' => 
        {
        'settings_here'           => 'Settings',
        'more_settings'           => 'More Settings'
        }
    );

%MENU_SECTIONS_HTML = ();

use Data::Dumper;
print header();

$menu_iterator = $MENU_SECTIONS->iterator;
while( (my $MENU_SECTION, my $MENU_ITEMS) = $menu_iterator->() ) 5
    {
    print "<hr>my $MENU_SECTION, my $MENU_ITEMS<br>";
    print "Dumper print of MENU_ITEMS:<br>";
    print Dumper $MENU_ITEMS;
    print "<br><br>";

    my $ITEM = Hash::Ordered->new(@MENU_ITEMS);
    $item_iterator = $ITEM->iterator;
    print "Dumper print of ITEM:<br>";
    print Dumper $ITEM;
    print "<br><br>";

    print "Dumper print of item_iterator:<br>";
    print Dumper $item_iterator;
    print "<br><br>";

    while( (my $OPERATION, my $TITLE) = $item_iterator->() ) 
        {
        print "my $OPERATION, my $TITLE<be>";
        }
    }

我得到的输出：

my MENU_manage_properties, my HASH(0x43a21f0)
Dumper print of MENU_ITEMS:
$VAR1 = { 'show_current_properties' => 'Current Properties', 'show_prospect_properties' => 'Prospect Properties' };

Dumper print of ITEM:
$VAR1 = bless( [ {}, [], undef, 0, 0 ], 'Hash::Ordered' );

Dumper print of item_iterator:
$VAR1 = sub { "DUMMY" };

my MENU_tenants, my HASH(0x4397b80)
Dumper print of MENU_ITEMS:
$VAR1 = { 'show_current_tenants' => 'Current Tenants', 'show_prospect_tenants' => 'Prospect Tenants' };

Dumper print of ITEM:
$VAR1 = bless( [ {}, [], undef, 0, 0 ], 'Hash::Ordered' );

Dumper print of item_iterator:
$VAR1 = sub { "DUMMY" };

my MENU_buyers, my HASH(0x4317590)
Dumper print of MENU_ITEMS:
$VAR1 = { 'show_prospect_buyers' => 'Prospect Buyers', 'show_current_buyers' => 'Current Buyers' };

Dumper print of ITEM:
$VAR1 = bless( [ {}, [], undef, 0, 0 ], 'Hash::Ordered' );

Dumper print of item_iterator:
$VAR1 = sub { "DUMMY" };

my MENU_reports, my HASH(0x43175f0)
Dumper print of MENU_ITEMS:
$VAR1 = { 'some_report' => 'Some report', 'another_report' => 'Another report' };

Dumper print of ITEM:
$VAR1 = bless( [ {}, [], undef, 0, 0 ], 'Hash::Ordered' );

Dumper print of item_iterator:
$VAR1 = sub { "DUMMY" };

my MENU_settings, my HASH(0x4317650)
Dumper print of MENU_ITEMS:
$VAR1 = { 'more_settings' => 'More Settings', 'settings_here' => 'Settings' };

Dumper print of ITEM:
$VAR1 = bless( [ {}, [], undef, 0, 0 ], 'Hash::Ordered' );

Dumper print of item_iterator:
$VAR1 = sub { "DUMMY" };

【问题讨论】：

总是use strict; use warnings。总是。你写了@MENU_ITEMS 而不是@$MENU_ITEMS； strict 会警告你的。
对，$MENU_ITEMS 不是数组引用，而是哈希引用。我不知道你想用它做什么，但你应该知道。无论如何，@MENU_ITEMS 不是一个存在的变量，因此您应该看到您的代码有问题。可能是%$MENU_ITEMS。
（尽管将无序散列转换为有序散列可能没有多大意义）
那是因为您使用{ ... } 创建了哈希，而您应该在第一个Hash::Ordered->new 中使用Hash::Ordered->new。
我想知道你是否不应该使用数组而不是哈希。

标签： perl hash

【解决方案1】：

感谢@Dada 的帮助，这里是工作代码：

use Hash::Ordered;
$MENU_SECTIONS = Hash::Ordered->new
    (
    'MENU_manage_properties' => 
        Hash::Ordered->new(
        'show_current_properties'  => 'Current Properties',
        'show_prospect_properties' => 'Prospect Properties'
        ),
    'MENU_reports' =>
        Hash::Ordered->new(
        'some_report'             => 'Some report',
        'another_report'          => 'Another report'
        ),
    'MENU_settings' =>
        Hash::Ordered->new(
        'settings_here'           => 'Settings',
        'more_settings'           => 'More Settings'
        )
    );


$menu_iterator = $MENU_SECTIONS->iterator;
while( (my $MENU_SECTION, my $MENU_ITEMS) = $menu_iterator->() )
    {
    my $ITEM = Hash::Ordered->new($MENU_ITEMS->as_list);
    $item_iterator = $ITEM->iterator;

    while( (my $OPERATION, my $TITLE) = $item_iterator->() )
        {
        ## DO something with $OPERATION and $TITLE
        }

    }

【讨论】：