您如何访问 Tie::IxHash 键？

Question

您好我需要从嵌套的 perl 哈希生成一个 xml 文档，并保持哈希键的顺序。我正在尝试 https://metacpan.org/pod/Tie::IxHash 为了保持钥匙的秩序部分。但是我不知道如何访问 Tie::IxHash 创建的散列键，它们的行为不像散列键、散列引用键或对象。在示例代码中，我创建了一个 Tie::IxHash 并尝试打印密钥 Transmitter 这是示例代码：

use strict;
use warnings;

use diagnostics;
use Scalar::Util;
use Data::Dumper;
use XML::Writer;
use Tie::IxHash;
use DateTime::Format::XSD;

my $time = time;


my $dt = DateTime->now;
my $timestamp = DateTime::Format::XSD->format_datetime($dt);
my $transmissionId = sprintf("%u",int(rand(100000000000000000000))). "E";


#sample data structure as hsah ref
# my $transmissionHeader = {
#       TransmissionId => "$transmissionId",
#       Timestamp => "$timestamp",
#       Transmitter => {
#           ETIN => '1232456789',
#               SOME => '5555555555',
#       }
#   };
    

my $transmissionHeader  = Tie::IxHash->new(
        TransmissionId => "$transmissionId",
        Timestamp => "$timestamp",
        Transmitter => Tie::IxHash->new( #each nested hash a new object?
            ETIN => '1232456789',
            SOME => '5555555555',
                                                                ),
    );
        
print Dumper $transmissionHeader;

# tried all these no joy
print "$transmissionHeader{Transmitter} \n";
print "$transmissionHeader->{Transmitter} \n";
print "$transmissionHeader->Transmitter() \n";

Answer 1

您可以使用Indices()方法获取键的索引，然后使用Values()方法获取该键的值：

my $idx = $transmissionHeader->Indices('Transmitter');
my $hash = $transmissionHeader->Values($idx);
print Dumper $hash;

您如何访问 Tie::IxHash 键？

How do you access Tie::IxHash keys?

perl