动态/递归地在Perl中构建哈希？ [英] Dynamically/recursively building hashes in Perl?

问题描述

我对Perl很陌生，我试图递归地构建一个散列并且无处可去。我试图寻找教程来动态构建哈希，但我能找到的只是关于哈希的介绍性文章。如果您将我指向正确的方向或者提出一篇不错的文章/教程，我将不胜感激。

我试图从一个文件中读取

 一/二/三
四
五/六/七/八
  

，我想构建一个像

  VAR = {
 one：{
二：{
三：
} 
} 
四：
五：{
六：{
七： {
 8：
} 
} 
} 
} 
  

我目前使用的脚本是：

  my $ finalhash = {}; 
 my @input =<>; 
 
 sub constructHash {
 my（$ hashrf，$ line）= @_; 
 @elements = split（/ \ //，$ line）; 
 if（@elements> 1）{
 $ hashrf-> {shift @elements} = constructHash（$ hashrf-> {$ elements [0]}，@elements）; 
} else {
 $ hashrf-> {shift @elements} =; 
} 
返回$ hashrf; 
 
 
 foreach $ lines（@input）{
 $ finalhash = constructHash（$ finalhash，$ lines）; 
 
  

解决方案

但它可以工作：

$ p $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ @ _;
if（@tail）{insert（\％{$ ref-> {$ head}}，@tail）}
else {$ ref-> {$ head} =''}
}

my％hash;
chomp并插入\％hash，split（'/'，$ _）while<>;

它依赖于autovivification，这对于初学者来说显然有点高级。

什么可能会让你的问题有点扭曲的答案是，你问叶中的空字符串，它与节点的哈希值是不同的类型，并且需要不同的解引用操作。

I'm quite new to Perl and I'm trying to build a hash recursively and getting nowhere. I tried searching for tutorials to dynamically build hashes, but all I could find were introductory articles about hashes. I would be grateful if you point me towards the right direction or suggest a nice article/tutorial.

I'm trying to read from a file which has paths in the form of

one/two/three
four
five/six/seven/eight

and I want to build a hash like

VAR = {
    one : {
        two : {
            three : ""
        }
    }
    four : ""
    five : {
        six : {
            seven : {
                 eight : ""
            }
        }
    }
}

The script I'm using currently is :

my $finalhash = {}; 
my @input = <>;

sub constructHash {
    my ($hashrf, $line) = @_; 
    @elements = split(/\//, $line);
    if(@elements > 1) {
        $hashrf->{shift @elements} = constructHash($hashrf->{$elements[0]}, @elements ); 
    } else {
        $hashrf->{shift @elements} = ""; 
    }
    return $hashrf;
}

foreach $lines (@input) {
    $finalhash = constructHash($finalhash, $lines);
}

解决方案

This is a bit far-fetched, but it works:

sub insert {
  my ($ref, $head, @tail) = @_;
  if ( @tail ) { insert( \%{$ref->{$head}}, @tail ) }
  else         {            $ref->{$head} = ''      }
}

my %hash;
chomp and insert \%hash, split( '/', $_ ) while <>;

It relies on autovivification, which is admittedly a bit advanced for a beginner.

What would probably make any answer to your question a bit twisted is that you ask for empty strings in the leaves, which is of a different "type" than the hashes of the nodes, and requires a different dereferencing operation.

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