Question

假设我有哈希数据结构的哈希结构如下：

%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,
     },

)

如何从最大到最小的值number_of_members对键（本例中的族）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++;
};

我希望打印代码（空格以制表符分隔）：

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

Answer 1

你走在正确的轨道上。您可以在哈希中使用$a和$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访问它们是最简单的。

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";
}

<强>输出：

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

按值Hash of Hashes Perl排序

1 个答案: