如何从perl中哈希内的数组中打印元素

Question

I'm trying to print the outputs from an API which are in multidimensional format.

use strict;
use warnings;
use Data::Dumper;

my $content={
  'school_set' => 'SSET1234',
  'result' => [
    {
      'school_name' => 'school_abc',
      'display_value' => 'IL25',
      'school_link' => 'example.com',
      'status' => 'registerd',
      'status_message' => 'only arts',
      'school_id' => '58c388d40596191f',
    }
  ],
  'school_table' => 'arts_schools'
};

print "school_name is=".$content{result}[0]{school_name};
print "school_status is=".$content{result}[3]{status};

output
Global symbol "%content" requires explicit package name (did you forget to declare "my %content"?) at test8.pl line 20.
Global symbol "%content" requires explicit package name (did you forget to declare "my %content"?) at test8.pl line 21.

I have to print the outputs like below from the result.

school_name = school_abc
school_status = registered

Answer 1

If $content is a hash reference, you need to dereference it first. Use the arrow operator for that:

$content->{result}[0]{school_name}

The syntax without the arrow is only possible for %content .

my %content = ( result => [ { school_name => 'abc' } ] );
print $content{result}[0]{school_name};

If you want to print all the results, you have to loop over the array somehow. For example

#!/usr/bin/perl
use warnings;
use strict;

my $content = {
    'result' => [
        {
            'school_name' => 'school_abc',
            'status' => 'registerd',
        },
        {
            'school_name' => 'school_def',
            'status' => 'pending',
        }
    ],
};

for my $school (@{ $content->{result} }) {
    print "school_name is $school->{school_name}, status is $school->{status}\n";

}

Answer 2

Your data structure assumes an array, perhaps it would be useful to utilize loop output for the data of interest.

The data presented as hash reference and will require de-referencing to loop through an array.

Following code snippet is based on your posted code and demonstrates how desired output can be achieved.

use strict;
use warnings;
use feature 'say';

my $dataset = {
              'school_set' => 'SSET1234',
              'result' => [
                {
                  'school_name' => 'school_abc',
                  'display_value' => 'IL25',
                  'school_link' => 'example.com',
                  'status' => 'registerd',
                  'status_message' => 'only arts',
                  'school_id' => '58c388d40596191f',
                }
              ],
              'school_table' => 'arts_schools'
            };

for my $item ( @{$dataset->{result}} ) {
    say "school_name is   = $item->{school_name}\n"
      . "school_status is = $item->{status}";
}

exit 0;

Output

school_name is   = school_abc
school_status is = registerd