保留从 Ruby 中的文件加载 YAML 的关键顺序

发布于 2024-11-06 10:59:09 字数 635 浏览 5 评论 0原文

我想保留从磁盘加载的 YAML 文件中键的顺序，以某种方式处理并写回磁盘。

以下是在 Ruby (v1.8.7) 中加载 YAML 的基本示例：

require 'yaml'

configuration = nil
File.open('configuration.yaml', 'r') do |file|
  configuration = YAML::load(file)
  # at this point configuration is a hash with keys in an undefined order
end

# process configuration in some way

File.open('output.yaml', 'w+') do |file|
  YAML::dump(configuration, file)
end

不幸的是，一旦构建了哈希，这将破坏 configuration.yaml 中键的顺序。我找不到控制 YAML::load() 使用什么数据结构的方法，例如 alib 的 orderedmap。

我没有运气在网上搜索解决方案。

原文

I want to preserve the order of the keys in a YAML file loaded from disk, processed in some way and written back to disk.

Here is a basic example of loading YAML in Ruby (v1.8.7):

require 'yaml'

configuration = nil
File.open('configuration.yaml', 'r') do |file|
  configuration = YAML::load(file)
  # at this point configuration is a hash with keys in an undefined order
end

# process configuration in some way

File.open('output.yaml', 'w+') do |file|
  YAML::dump(configuration, file)
end

Unfortunately, this will destroy the order of the keys in configuration.yaml once the hash is built. I cannot find a way of controlling what data structure is used by YAML::load(), e.g. alib's orderedmap.

I've had no luck searching the web for a solution.

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删除会话 2024-11-13 10:59:09

使用 Ruby 1.9.x。以前版本的 Ruby 不保留哈希键的顺序，但 1.9 则保留。

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把回忆走一遍 2024-11-13 10:59:09

如果您出于某种原因而无法使用 1.8.7（就像我一样），我会求助于使用 active_support/ordered_hash。我知道 activesupport 似乎是一个很大的包含，但他们在以后的版本中将其重构为您几乎只需要文件中需要的部分，而其余部分则被忽略。只需gem install activesupport，并包含它，如下所示。另外，在 YAML 文件中，请务必使用 !!omap 声明（和哈希数组）。举例时间！

# config.yml #

months: !!omap
  - january: enero
  - february: febrero
  - march: marzo
  - april: abril
  - may: mayo

这是它背后的 Ruby 的样子。

# loader.rb #

require 'yaml'
require 'active_support/ordered_hash'

# Load up the file into a Hash
config = File.open('config.yml','r') { |f| YAML::load f }

# So long as you specified an !!omap, this is actually a
# YAML::PrivateClass, an array of Hashes
puts config['months'].class

# Parse through its value attribute, stick results in an OrderedHash,
# and reassign it to our hash
ordered = ActiveSupport::OrderedHash.new
config['months'].value.each { |m| ordered[m.keys.first] = m.values.first }
config['months'] = ordered

我正在寻找一种解决方案，允许我递归地挖掘从 .yml 文件加载的 Hash，查找那些 YAML::PrivateClass 对象，并将它们转换为 ActiveSupport::OrderedHash。我可能会就此提出问题。

If you're stuck using 1.8.7 for whatever reason (like I am), I've resorted to using active_support/ordered_hash. I know activesupport seems like a big include, but they've refactored it in later versions to where you pretty much only require the part you need in the file and the rest gets left out. Just gem install activesupport, and include it as shown below. Also, in your YAML file, be sure to use an !!omap declaration (and an array of Hashes). Example time!

# config.yml #

months: !!omap
  - january: enero
  - february: febrero
  - march: marzo
  - april: abril
  - may: mayo

Here's what the Ruby behind it looks like.

# loader.rb #

require 'yaml'
require 'active_support/ordered_hash'

# Load up the file into a Hash
config = File.open('config.yml','r') { |f| YAML::load f }

# So long as you specified an !!omap, this is actually a
# YAML::PrivateClass, an array of Hashes
puts config['months'].class

# Parse through its value attribute, stick results in an OrderedHash,
# and reassign it to our hash
ordered = ActiveSupport::OrderedHash.new
config['months'].value.each { |m| ordered[m.keys.first] = m.values.first }
config['months'] = ordered

I'm looking for a solution that allows me to recursively dig through a Hash loaded from a .yml file, look for those YAML::PrivateClass objects, and convert them into an ActiveSupport::OrderedHash. I may post a question on that.

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