从字符串生成嵌套散列并在Ruby中进行深度合并 [英] Generate nested hashes from strings and deep merging in ruby

问题描述

我在JSON格式的数据库中有一个散列。例如

  {
one=> {
two=> {
three=> {} 
} 
} 
} 
  

我需要生成这来自一个字符串。上面的例子将由字符串one.two.three生成。

首先，我该怎么做？

问题的第二部分。我会收到多个字符串 - 每个字符串都是最后一个字符串。所以，如果我得到one.two.three，那么one.two.four，我哈希是这样的：

  {
one=> {
two=> {
three=> {}，
four=> {} 
} 
} 
} 
  

如果我得到one.two.three两次，我想要最新的三值来覆盖那里。字符串也可以是任意长度的（例如one.two.three.four.five或者one）。希望这是有道理的？

解决方案

要生成嵌套的哈希值：

 hash = {} 
 
one.two.three.split（'。'）。reduce（hash）{| h，m | h [m] = {}} 
 
 puts hash＃=> {one=> {two=> {three=> {}}}} 
  

如果您没有安装rails，请安装activesupport gem：

  gem install activesupport 
  

然后将其包含到您的文件中：

  require'active_support / core_ext / hash / deep_merge'
 
 hash = {
one=> {
two=> {
three=> {} 
} 
} 
} .deep_merge（another_hash）
  

对内部的访问将是：

$ p $ hash $ ['one'] ['two'] ['three']＃ => {}

I have a hash in the database in JSON format. eg

{
  "one" => {
    "two" => {
      "three" => {}
    }
  } 
}

I need to generate this from a string. The above example would be generated from the string "one.two.three".

Firstly how would I do this?

Second part of the problem. I will be receiving multiple strings - each one building on the last. So if I get "one.two.three", then "one.two.four", I hash to be this:

{
  "one" => {
    "two" => {
      "three" => {},
      "four" => {}
    }
  } 
}

And if I get "one.two.three" twice, I want the latest "three" value to override what was there. Strings can also be of any length (e.g. "one.two.three.four.five" or just "one"). Hopefully that makes sense?

解决方案

To generate nested hash:

hash = {}

"one.two.three".split('.').reduce(hash) { |h,m| h[m] = {} }

puts hash #=> {"one"=>{"two"=>{"three"=>{}}}}

If you don't have rails installed then install activesupport gem:

gem install activesupport

Then include it into your file:

require 'active_support/core_ext/hash/deep_merge'

hash = {
  "one" => {
    "two" => {
      "three" => {}
    }
  } 
}.deep_merge(another_hash)

The access to the internals would be:

hash['one']['two']['three'] #=> {}

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