json - 在 perl 中访问 json 结构的值

Question

我有一个正在解码的 json 结构，如下所示:

  person => {
    city => "Chicago",
    id => 123,
    name => "Joe Smith",
    pets => {
      cats => [
                { age => 6, name => "cat1", type => "siamese", weight => "10 kilos" },
                { age => 10, name => "cat2", type => "siamese", weight => "13 kilos" },
              ],
      dogs => [
                { age => 7, name => "dog1", type => "siamese", weight => "20 kilos" },
                { age => 5, name => "dog2", type => "siamese", weight => "15 kilos" },
              ],
    },
  },
}

我可以打印 city , id , name通过做:

foreach my $listing ($decoded->{person})
{ 
    my $city = $listing->{city};
    my $name = $listing->{name};
    name - $city - \n";
}

但是，我不确定如何打印 pets->cats或 pets->dogs .我可以通过以下方式转储它们:

my @pets = $listing->{pets}->{cats};
dump @pets;

但我不确定如何通过哈希结构访问它们。

Answer 1

假设您的 $listing是一个你必须取消引用数组和散列引用的人。

# as long as we are assuming $listing is a person
# this goes inside the foreach you posted in your
# question.

# this will print all cats' names
foreach my $cat ( @{ $listing->{pets}->{cats} } )
{
    # here $cat is a hash reference

    say $cat->{name}; # cat's name
}

等等其他东西。

要从结构中访问它们，您可以执行以下操作:

say $listing->{pets}->{cats}->[0]->{name}; # this will print 'cat1'