我是 perl 的初学者，我有一个不知道如何解决的问题。我试图从网站获取 xml 数据并将温度值放入数组中。

到目前为止，这是我的代码:

use strict;
use warnings;

# For parsing
use XML::Simple;

# For downloading
use LWP::Simple;

# For debug output
use Data::Dumper;

# Turn off output buffering
$|=1;

# Note, no error checking here!

sub main 
{

    print "\nDownloading ....";
    my $data = get('http://www.yr.no/place/Norway/Telemark/Sauherad/Gvarv/forecast_hour_by_hour.xml');

    my $parser = new XML::Simple;

    print "\nParsing ...";
    my $dom = $parser->XMLin($data);

    print "\n\n";

    # Debug output. 
    #print Dumper($dom->{'forecast'});

    # Data structure is a hash containing one key, 'entry'.
    # Get the hash value and cast to an array.
    my @entries = $dom->{'forecast'}->{'tabular'}->{'time'};
    # Go through each array 'entry' element.
    foreach my $entry(@entries) 
    {   
        print Dumper($entry);
        # Each element is a hash.
        # The band name can be got from one hash key.
        my $tabular = $entry->{'temperature'};


        #print "$tabular\n";


        print "\n\n";
    }


}

main();

我在终端上得到的输出是:

    },
      {
        'temperature' => {
                         'unit' => 'celsius',
                         'value' => '26'
                       },
        'windSpeed' => {
                       'name' => 'Light breeze',
                       'mps' => '1.9'
                     },
        'to' => '2016-08-17T16:00:00',
        'pressure' => {
                      'unit' => 'hPa',
                      'value' => '1014.1'
                    },
        'from' => '2016-08-17T15:00:00',
        'precipitation' => {
                           'value' => '0'
                         },
        'symbol' => {
                    'numberEx' => '1',
                    'var' => '01d',
                    'number' => '1',
                    'name' => 'Clear sky'
                  },
        'windDirection' => {
                           'name' => 'North',
                           'code' => 'N',
                           'deg' => '4.4'
                         }
      },
      {
        'precipitation' => {
                           'value' => '0'
                         },
        'from' => '2016-08-17T16:00:00',
        'windDirection' => {
                           'name' => 'North-northeast',
                           'code' => 'NNE',
                           'deg' => '20.6'
                         },
        'symbol' => {
                    'number' => '1',
                    'name' => 'Clear sky',
                    'var' => '01d',
                    'numberEx' => '1'
                  },
        'temperature' => {
                         'unit' => 'celsius',
                         'value' => '27'
                       },
        'pressure' => {
                      'value' => '1013.4',
                      'unit' => 'hPa'
                    },
        'to' => '2016-08-17T17:00:00',
        'windSpeed' => {
                       'mps' => '1.2',
                       'name' => 'Light air'
                     }
      },
      {
        'symbol' => {
                    'numberEx' => '1',
                    'var' => '01d',
                    'name' => 'Clear sky',
                    'number' => '1'
                  },
        'windDirection' => {
                           'name' => 'East',
                           'code' => 'E',
                           'deg' => '83.0'
                         },
        'from' => '2016-08-17T17:00:00',
        'precipitation' => {
                           'value' => '0'
                         },
        'windSpeed' => {
                       'mps' => '0.7',
                       'name' => 'Light air'
                     },
        'pressure' => {
                      'unit' => 'hPa',
                      'value' => '1012.8'
                    },
        'to' => '2016-08-17T18:00:00',
        'temperature' => {
                         'unit' => 'celsius',
                         'value' => '27'
                       }
      }
    ];
Not a HASH reference at script.pl line 43.

为什么会出现此错误以及如何获取温度值？提前致谢!

最佳答案

XML::Simple告诉你不要使用它。听从它的建议。

以下是使用 XML::LibXML 提取温度的方法:

#!/usr/bin/perl

use warnings;
use strict;
use feature qw{ say };

use XML::LibXML;

my $dom = 'XML::LibXML'->load_xml(
    location => 'http://www.yr.no/place/Norway/Telemark/Sauherad/Gvarv/forecast_hour_by_hour.xml');

for my $temperature ($dom->findnodes('//temperature/@value')) {
    say $temperature->getValue;
}

与 xsh ，它是 XML::LibXML 的包装器，你可以只写

open http://www.yr.no/place/Norway/Telemark/Sauherad/Gvarv/forecast_hour_by_hour.xml ;
for //temperature echo @value ;

关于xml - 我如何在 perl 中获取 xml 值？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/38958586/