perl 在主哈希中创建子哈希

kupeojn6 于 2022-11-15 发布在 Perl

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我想在Perl中创建一个hash值的hash，而不必显式地写出所有内容。我知道我可以使用dclone来做类似这样的事情：

use Storable 'dclone';

my %main_hash = (
   A => {},
   B => {},
   C => {},
);

my %sub_hash = (
   a => [],
   b => [],
   c => [],
   d => [],
);

foreach my $main_key (keys %main_hash) {
   $main_hash{$main_key} = dclone {%sub_hash};
}

最终结果：

%main_hash:
   A => {
     a => [],
     b => [],
     c => [],
     d => [],
   },
   B => {
     a => [],
     b => [],
     c => [],
     d => [],
   },
   C => {
     a => [],
     b => [],
     c => [],
     d => [],
   },
);

有没有办法在不依赖dclone或其他导入的模块的情况下重复进行哈希插入？

perl

来源：https://stackoverflow.com/questions/73309079/creating-sub-hashes-in-main-hash

2条答案

按热度按时间

roejwanj1#

你可以把%sub_hash声明放在循环中，并把它赋给主哈希值，每次循环迭代都是一个新的哈希值，你不需要dclone：

my %main_hash = (
   A => {},
   B => {},
   C => {},
);

foreach my $main_key (keys %main_hash) {
    my %sub_hash = (
       a => [],
       b => [],
       c => [],
       d => [],
    );
   $main_hash{$main_key} = \%sub_hash;
}

use Data::Dumper;
print Dumper \%main_hash;

输出量：

$VAR1 = {
          'C' => {
                   'b' => [],
                   'a' => [],
                   'c' => [],
                   'd' => []
                 },
          'B' => {
                   'b' => [],
                   'a' => [],
                   'c' => [],
                   'd' => []
                 },
          'A' => {
                   'c' => [],
                   'd' => [],
                   'b' => [],
                   'a' => []
                 }
        };

赞(0）回复(0）举报 2022-11-15

f0brbegy2#

请检查下面的代码片段，它利用两个索引生成一个散列--以符合您的问题。

use strict;
use warnings;
use feature 'say';

use Data::Dumper;

my %hash;

for my $main_key ( qw/A B C/ ) {
    for my $sub_key ( qw/a b c d/ ) {
        $hash{$main_key}{$sub_key} = [];
    }
}

say Dumper(\%hash);

输出量

$VAR1 = {
          'C' => {
                   'c' => [],
                   'd' => [],
                   'a' => [],
                   'b' => []
                 },
          'B' => {
                   'b' => [],
                   'a' => [],
                   'c' => [],
                   'd' => []
                 },
          'A' => {
                   'c' => [],
                   'd' => [],
                   'b' => [],
                   'a' => []
                 }
        };

赞(0）回复(0）举报 2022-11-15

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perl 在主哈希中创建子哈希

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