按值哈希排序 Perl

Question

假设我有一个哈希数据结构的哈希构造如下：

%HoH => (
     flintstones => {
               family_members    => "fred;wilma;pebbles;dino",
               number_of_members => 4,
     },
     jetsons => {
               family_members    => "george;jane;elroy",
               number_of_members => 3,
     },
     simpsons => {
               family_members    => "homer;marge;bart;lisa;maggie",
               number_of_members => 5,
     },

)

如何按值number_of_members 从大到小对键（在这种情况下为家庭）进行排序？然后我想打印出最高的两个。这是一个大致的想法，但我知道这是错误的：

foreach $value (
    sort {
    $HoH{$a}{$number_of_members} cmp $HoH{$b}{$number_of_members}
    } keys %HoH)
my $count = 0;
while ($key, $value) = each %HoH) {
    if (count <= 2){
        print "${HoH}{$key}\t$key{$value}";
    }
}
continue {
    $count++;
};

我想要打印代码（空格是制表符分隔的）：

simpsons    homer;marge;bart;lisa;maggie
flintstones    fred;wilma;pebbles;dino

Answer 1

你在正确的轨道上。您在散列中使用 $a 和 $b 内部变量并以数字方式比较值（<=> 而不是 cmp）。

打印时，我发现将键存储在数组中并使用数组切片来访问它们是最简单的方法。

use strict;
use warnings;

my %HoH = (
     flintstones => {
               family_members    => "fred;wilma;pebbles;dino",
               number_of_members => 4,
     },
     jetsons => {
               family_members    => "george;jane;elroy",
               number_of_members => 3,
     },
     simpsons => {
               family_members    => "homer;marge;bart;lisa;maggie",
               number_of_members => 5,
     },    
);
my @sorted = sort { $HoH{$b}{'number_of_members'} <=> 
                    $HoH{$a}{'number_of_members'} } keys %HoH;

for (@sorted[0,1]) {   # print only first two
    print join("\t", $_, $HoH{$_}{'family_members'}), "\n";
}

输出：

simpsons        homer;marge;bart;lisa;maggie
flintstones     fred;wilma;pebbles;dino