如何将对象保存到文件中？

发布于 2024-10-04 22:07:16 字数 254 浏览 5 评论 0原文

我想将对象保存到文件中，然后轻松地从文件中读取它。举一个简单的例子，假设我有以下 3d 数组：

m = [[[0, 0, 0],
 [0, 0, 0],
 [0, 0, 0]],
[[0, 0, 0],
 [0, 0, 0],
 [0, 0, 0]]]

是否有一个简单的 Ruby API 可以用来实现此目的，而无需编写解析器来解释文件中的数据？在我给出的示例中，这很简单，但是随着对象变得更加复杂，使对象持久化会变得很烦人。

原文

I would like to save an object to a file, and then read it from the file easily. As a simple example, lets say I have the following 3d array:

m = [[[0, 0, 0],
 [0, 0, 0],
 [0, 0, 0]],
[[0, 0, 0],
 [0, 0, 0],
 [0, 0, 0]]]

Is there an easy Ruby API that I can use to achieve this without programming a parser to interpret the data from the file? In the example I give it is easy, but as the objects become more complicated, it gets annoying to make objects persistent.

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怕倦 2024-10-11 22:07:17

YAML 和 Marshal 是最明显的答案，但根据您计划如何处理数据，sqlite3 也可能是一个有用的选项。

require 'sqlite3'

m = [[[0, 0, 0],
 [0, 0, 0],
 [0, 0, 0]],
[[0, 0, 0],
 [0, 0, 0],
 [0, 0, 0]]]

db=SQLite3::Database.new("demo.out")
db.execute("create table data (x,y,z,value)")
inserter=db.prepare("insert into data (x,y,z,value) values (?,?,?,?)")
m.each_with_index do |twod,z|
  twod.each_with_index do |row,y|
    row.each_with_index do |val,x|
      inserter.execute(x,y,z,val)
    end
  end
end

YAML and Marshal are the most obvious answers, but depending on what you're planning to do with the data, sqlite3 may be a useful option too.

require 'sqlite3'

m = [[[0, 0, 0],
 [0, 0, 0],
 [0, 0, 0]],
[[0, 0, 0],
 [0, 0, 0],
 [0, 0, 0]]]

db=SQLite3::Database.new("demo.out")
db.execute("create table data (x,y,z,value)")
inserter=db.prepare("insert into data (x,y,z,value) values (?,?,?,?)")
m.each_with_index do |twod,z|
  twod.each_with_index do |row,y|
    row.each_with_index do |val,x|
      inserter.execute(x,y,z,val)
    end
  end
end

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负佳期 2024-10-11 22:07:16

您需要先序列化对象，然后才能将它们保存到文件并反序列化它们以检索它们。正如 Cory 提到的，有 2 个标准序列化库被广泛使用， Marshal 和 YAML。

Marshal 和 YAML 分别使用 dump 和 load 方法进行序列化和反序列化。

以下是如何使用它们：

m = [
     [
      [0, 0, 0],
      [0, 0, 0],
      [0, 0, 0]
     ],
     [
      [0, 0, 0],
      [0, 0, 0],
      [0, 0, 0]
     ]
    ]

# Quick way of opening the file, writing it and closing it
File.open('/path/to/yaml.dump', 'w') { |f| f.write(YAML.dump(m)) }
File.open('/path/to/marshal.dump', 'wb') { |f| f.write(Marshal.dump(m)) }

# Now to read from file and de-serialize it:
YAML.load(File.read('/path/to/yaml.dump'))
Marshal.load(File.read('/path/to/marshal.dump'))

您需要注意文件大小以及与文件读/写相关的其他问题。

更多信息当然可以在 API 文档中找到。

You need to serialize the objects before you could save them to a file and deserialize them to retrieve them back. As mentioned by Cory, 2 standard serialization libraries are widely used, Marshal and YAML.

Both Marshal and YAML use the methods dump and load for serializing and deserializing respectively.

Here is how you could use them:

m = [
     [
      [0, 0, 0],
      [0, 0, 0],
      [0, 0, 0]
     ],
     [
      [0, 0, 0],
      [0, 0, 0],
      [0, 0, 0]
     ]
    ]

# Quick way of opening the file, writing it and closing it
File.open('/path/to/yaml.dump', 'w') { |f| f.write(YAML.dump(m)) }
File.open('/path/to/marshal.dump', 'wb') { |f| f.write(Marshal.dump(m)) }

# Now to read from file and de-serialize it:
YAML.load(File.read('/path/to/yaml.dump'))
Marshal.load(File.read('/path/to/marshal.dump'))

You need to be careful about the file size and other quirks associated with File reading / writing.

More info, can of course be found in the API documentation.

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