从数组创建一个散列的多维密钥？ [英] Create a multidimesional key of hash from array?

问题描述

我想从 @array 创建一个多维％hash 。

假设 @array 就像

 我的@阵列=（1,2,3,4,5）; 
  

我想分配 @array 上一个值作为多维％散列的最终值，即

 ％hash =（
 1 => {
 2 => 
 {
 3 => 
 {
 4 => 5 
} 
 
 
 
 
 
 $ b $这意味着 $ hash {1} {2} {3} {4} = 5;  
 
 
 
我想这样做：对于我的$ i（0 .. $＃数组），
 
 
 {
 #push $ i作为关键字，直到倒数第二个元素和将最后一个元素赋值为
} 
  
注意： @array 可以是任何大小，只是我想给 @array 中最后一个元素之前的元素键指定最后一个元素 c $ c>％hash 。
解决方案
首先，使用 pop 分隔要从键分配的值。然后，您可以使用以下任一项： 
 
 
 使用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 通过 $ p 引用下一个取消引用和/或修改的值。 
 
 
 预回路： $ p引用$ hash（引用％散列的匿名标量）
循环传递之后0：$ p引用$ hash-> {1} 
循环传递1之后：$ p引用$ hash-> {1} {2} 
循环传递2之后：$ p引用$ hash-> {1} {2} {3} 
循环传递3之后：$ p引用$ hash-> { 1} {2} {3} {4} 
  
额外的间接级别有很多好处。 / b> 
 
 
 
 
它不需要专门处理最后一个键。 
 
它不需要创建在解除引用之前进行散列。   
 
它不需要将根作为对散列的引用。相反，任何标量都可以是根，甚至可以是未定义的。
 
 
它可以很容易地扩展 dive_val 来支持混合数组/散列结构。
 
 
 
I want to create a multidimensional %hash from the @array.

Suppose @array is like 
my @array=(1,2,3,4,5);
I want to assign @array last value as final value to multidimensional %hash i.e 
%hash=(
        1=>{ 
              2=>
                 {
                  3=>
                      {
                        4=>5
                       }
                  }
              }
           )
Which means $hash{1}{2}{3}{4}=5;

I want to do it in something like:
for my $i (0..$#array){
    #push $i as key until second last element and assign last element as value
} 
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.
解决方案
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;
or
sub dive_val :lvalue {
   my $p = \shift;
   $p = \( $$p->{$_} ) for @_;
   $$p
}

my %hash;
dive_val(\%hash, @keys) = $val;
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}
The extra level of indirection has many benefits.


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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