perl - 然后按子键对键排序——如果子键 undef 设置为空字符串

Question

my %data (
    KEY1 => {
        SUBKEY1 => "Canada",
        SUBKEY3 => "75.00",
        SUBKEY2 => "50.00",    
    },
    KEY3 => {
        SUBKEY2 => "150.00",
    },  
    KEY2 => { 
        SUBKEY3 => "200.00",
        SUBKEY1 => "Mexico",
 },
);

如何打印按键名排序并按子键名排序的每个键名的列表？

这是我要打印的内容:(请注意，如果未定义子项，则会出现一个带有空字符串的子项的占位符)

KEY1: SUBKEY1 is "Canada"
KEY1: SUBKEY2 is "50.00"
KEY1: SUBKEY3 is "75.00"
KEY2: SUBKEY1 is ''
KEY2: SUBKEY2 is "150.00"
KEY2: SUBKEY3 is ''
KEY3: SUBKEY1 is "Mexico"
KEY3: SUBKEY2 is ''
KEY3: SUBKEY3 is "200.00"

Answer 1

use strict;
use warnings;

my %data = (
    KEY1 => {
        SUBKEY1 => "Canada",
        SUBKEY3 => "75.00",
        SUBKEY2 => "50.00",    
    },
    KEY3 => {
        SUBKEY2 => "150.00",
    },  
    KEY2 => { 
        SUBKEY3 => "200.00",
        SUBKEY1 => "Mexico",
 },
);

my %all_sub_keys;
for my $sub_hash (values %data){
    $all_sub_keys{$_} ++ for keys %$sub_hash;
}

my @all_sub_keys = sort keys %all_sub_keys;

for my $k ( sort keys %data ){
    for my $sk (@all_sub_keys){
        my $val = exists $data{$k}{$sk} ? $data{$k}{$sk} : '--';
        print join(' ', $k, $sk, $val), "\n";
    }
}