如何在Perl结构中访问键的特定值? [英] how to access a specific value of a key within a Perl structure?

问题描述

假定Geo::Coder::Google数据转储的这种结构--- dd $location;.

Assume this structure of a Geo::Coder::Google data dump --- dd $location;.

  address_components => [
    {
      long_name => "Blackheath Avenue",
      short_name => "Blackheath Ave",
      types => ["route"],
    },
    {
      long_name => "Greater London",
      short_name => "Gt Lon",
      types => ["administrative_area_level_2", "political"],
    },
    {
      long_name => "United Kingdom",
      short_name => "GB",
      types => ["country", "political"],
    },
    {
      long_name => "SE10 8XJ",
      short_name => "SE10 8XJ",
      types => ["postal_code"],
    },
    { long_name => "London", short_name => "London", types => ["postal_town"] },
  ],
  formatted_address => "Blackheath Avenue, London SE10 8XJ, UK",
  geometry => {
    bounds        => {
      northeast => { lat => 51.4770228, lng => 0.0005404 },
      southwest => { lat => 51.4762273, lng => -0.0001147 },
    },
    location      => { lat => 51.4766277, lng => 0.0002212 },
    location_type => "APPROXIMATE",
    viewport      => {
      northeast => { lat => 51.4779740302915, lng => 0.00156183029150203 },
      southwest => { lat => 51.4752760697085, lng => -0.00113613029150203 },
    },
  },
  types => ["route"],
}

一个示例调用:

my $long_name = &get_field_for_location("long_name", $location);

随后的sub返回第一个long_name(在本示例中为--type = route):

Following sub returns the first long_name (in this example --- type=route):

sub get_field_for_location($$) {
  my $field    = shift;
  my $location = shift;

  my $address = $location->{address_components};
  return $_->{$field} for @$address;
}

如何访问其他类型的long_name?即如何修改此子项以访问给定类型条目的$field?

How to access a long_name of another type? i.e. how to modify this sub to access a $field for a given type entry?

推荐答案

它应首先返回类型为political，

my $type = "political";

my ($first_of_type) =  grep { 
  grep { $_ eq $type } @{$_->{types}}; 
} @$address;

return $first_of_type->{$field};

外部grep过滤@$address数组的元素，内部grep过滤types数组的元素，即. ["administrative_area_level_2", "political"]

Outer grep filters elements of @$address array, and inner grep filters elements of types, ie. ["administrative_area_level_2", "political"]

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