从数组创建哈希的多维键? [英] Create a multidimesional key of hash from array?

问题描述

我想从 @array 创建一个多维的 %hash.

I want to create a multidimensional %hash from the @array.

假设 @array 就像

my @array=(1,2,3,4,5);

我想将 @array 最后一个值作为最终值分配给多维 %hash 即

I want to assign @array last value as final value to multidimensional %hash i.e

%hash=(
        1=>{ 
              2=>
                 {
                  3=>
                      {
                        4=>5
                       }
                  }
              }
           )

这意味着 $hash{1}{2}{3}{4}=5;

我想这样做:

for my $i (0..$#array){
    #push $i as key until second last element and assign last element as value
} 

注意:@array 可以是任意大小，只是我想将 @array 的最后一个元素作为值分配给最后一个元素之前的元素的键%hash.

Note : The @array may be of any size, Just I want to assign last element of @array as value to the keys of elements before the last element in %hash.

推荐答案

首先，使用 pop 将要分配的值与键分开.然后，您可以使用以下任一方法:

First, use pop to separate the value to assign from the keys. Then, you can use either of the following:

use Data::Diver qw( DiveVal );

my %hash;
DiveVal(\%hash, map \$_, @keys) = $val;

或

sub dive_val :lvalue {
   my $p = \shift;
   $p = \( $$p->{$_} ) for @_;
   $$p
}

my %hash;
dive_val(\%hash, @keys) = $val;

dive_val 的工作原理是让 $p 引用下一个值以取消引用和/或修改.

dive_val works by having $p reference the next value to dereference and/or modify.

Pre-loop:            $p references $hash (the anon scalar referencing %hash)
After loop pass 0:   $p references $hash->{1}
After loop pass 1:   $p references $hash->{1}{2}
After loop pass 2:   $p references $hash->{1}{2}{3}
After loop pass 3:   $p references $hash->{1}{2}{3}{4}

额外的间接级别有很多好处.

The extra level of indirection has many benefits.

• 它不需要特别对待最后一个键.
• 它消除了在取消引用之前创建哈希的需要.
• 它消除了将根作为对哈希的引用的需要.相反，任何标量都可以是根，甚至是未定义的.
• 它可以轻松扩展 dive_val 以支持混合数组/哈希结构.

• It removes the need to treat the last key specially.
• It removes the need to create the hash before it's dereferenced.
• It removes the need for the root to be a reference to a hash. Instead, any scalar can be the root, even an undefined one.
• It makes it easy to extend dive_val to support mixed array/hash structures.

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