ruby 如何使用 Nokogiri 解析 XML 文件？
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How do I use Nokogiri to parse an XML file?
提问by camdixon
I'm having some issues with Nokogiri.
我对 Nokogiri 有一些问题。
I am trying to parse this XML file:
我正在尝试解析这个 XML 文件：
<Collection version="2.0" id="74j5hc4je3b9">
<Name>A Funfair in Bangkok</Name>
<PermaLink>Funfair in Bangkok</PermaLink>
<PermaLinkIsName>True</PermaLinkIsName>
<Description>A small funfair near On Nut in Bangkok.</Description>
<Date>2009-08-03T00:00:00</Date>
<IsHidden>False</IsHidden>
<Items>
<Item filename="AGC_1998.jpg">
<Title>Funfair in Bangkok</Title>
<Caption>A small funfair near On Nut in Bangkok.</Caption>
<Authors>Anthony Bouch</Authors>
<Copyright>Copyright ? Anthony Bouch</Copyright>
<CreatedDate>2009-08-07T19:22:08</CreatedDate>
<Keywords>
<Keyword>Funfair</Keyword>
<Keyword>Bangkok</Keyword>
<Keyword>Thailand</Keyword>
</Keywords>
<ThumbnailSize width="133" height="200" />
<PreviewSize width="532" height="800" />
<OriginalSize width="2279" height="3425" />
</Item>
<Item filename="AGC_1164.jpg" iscover="True">
<Title>Bumper Cars at a Funfair in Bangkok</Title>
<Caption>Bumper cars at a small funfair near On Nut in Bangkok.</Caption>
<Authors>Anthony Bouch</Authors>
<Copyright>Copyright ? Anthony Bouch</Copyright>
<CreatedDate>2009-08-03T22:08:24</CreatedDate>
<Keywords>
<Keyword>Bumper Cars</Keyword>
<Keyword>Funfair</Keyword>
<Keyword>Bangkok</Keyword>
<Keyword>Thailand</Keyword>
</Keywords>
<ThumbnailSize width="200" height="133" />
<PreviewSize width="800" height="532" />
<OriginalSize width="3725" height="2479" />
</Item>
</Items>
</Collection>
I want all of that information displayed to the screen, that's it. Should be simple right? I am doing this:
我希望所有这些信息都显示在屏幕上，就是这样。应该很简单吧？我正在这样做：
require 'nokogiri'
doc = Nokogiri::XML(File.open("sample.xml"))
@block = doc.css("items item").map {|node| node.children.text}
puts @block
Each Itemsis a node, and under that there are children nodes of Item?
每个Items都是一个节点，在其下有Item?
I create a map of this, which returns a hash, and the code in {}goes through each node and places the children text into @block.
Then I can display all of the child node's text to the screen.
我创建了一个映射，它返回一个散列，代码{}遍历每个节点并将子文本放入@block. 然后我可以将所有子节点的文本显示到屏幕上。
I have no idea how far or close I am, because I've read so many articles, and am still a little confused on the basics especially since usually with a new language, I read from a file and output to the screen for a basic program.
我不知道我有多远或多近，因为我读了很多文章，但对基础知识仍然有点困惑，特别是因为通常使用一种新语言，我从文件中读取并输出到屏幕以获得基本的程序。
回答by Arup Rakshit
Here I will try to explain you all the questions/confusions you are having:
在这里，我将尝试向您解释您遇到的所有问题/困惑：
require 'nokogiri'
doc = Nokogiri::XML.parse <<-XML
<Collection version="2.0" id="74j5hc4je3b9">
<Name>A Funfair in Bangkok</Name>
<PermaLink>Funfair in Bangkok</PermaLink>
<PermaLinkIsName>True</PermaLinkIsName>
<Description>A small funfair near On Nut in Bangkok.</Description>
<Date>2009-08-03T00:00:00</Date>
<IsHidden>False</IsHidden>
<Items>
<Item filename="AGC_1998.jpg">
<Title>Funfair in Bangkok</Title>
<Caption>A small funfair near On Nut in Bangkok.</Caption>
<Authors>Anthony Bouch</Authors>
<Copyright>Copyright ? Anthony Bouch</Copyright>
<CreatedDate>2009-08-07T19:22:08</CreatedDate>
<Keywords>
<Keyword>Funfair</Keyword>
<Keyword>Bangkok</Keyword>
<Keyword>Thailand</Keyword>
</Keywords>
<ThumbnailSize width="133" height="200" />
<PreviewSize width="532" height="800" />
<OriginalSize width="2279" height="3425" />
</Item>
<Item filename="AGC_1164.jpg" iscover="True">
<Title>Bumper Cars at a Funfair in Bangkok</Title>
<Caption>Bumper cars at a small funfair near On Nut in Bangkok.</Caption>
<Authors>Anthony Bouch</Authors>
<Copyright>Copyright ? Anthony Bouch</Copyright>
<CreatedDate>2009-08-03T22:08:24</CreatedDate>
<Keywords>
<Keyword>Bumper Cars</Keyword>
<Keyword>Funfair</Keyword>
<Keyword>Bangkok</Keyword>
<Keyword>Thailand</Keyword>
</Keywords>
<ThumbnailSize width="200" height="133" />
<PreviewSize width="800" height="532" />
<OriginalSize width="3725" height="2479" />
</Item>
</Items>
</Collection>
XML
So from my understanding of Nokogiri, each 'Items' is a node, and under that there are children nodes of 'Item'?
所以根据我对 Nokogiri 的理解，每个 'Items' 都是一个节点，在它下面有 'Item' 的子节点？
No, each Itemsare Nokogiri::XML::NodeSet. And under that there are 2 children nodes of Items,which are of Nokogiri::XML::Elementclass object. You can say them also Nokogiri::XML::Node
不，每个项目都是Nokogiri::XML::NodeSet。在其下有Items 的2 个子节点，它们是Nokogiri::XML::Element类对象。你也可以说他们Nokogiri::XML::Node
doc.class # => Nokogiri::XML::Document
@block = doc.xpath("//Items/Item")
@block.class # => Nokogiri::XML::NodeSet
@block.count # => 2
@block.map { |node| node.name }
# => ["Item", "Item"]
@block.map { |node| node.class }
# => [Nokogiri::XML::Element, Nokogiri::XML::Element]
@block.map { |node| node.children.count }
# => [19, 19]
@block.map { |node| node.class.superclass }
# => [Nokogiri::XML::Node, Nokogiri::XML::Node]
We create a map of this, which returns a hash I believe, and the code in {} goes through each node and places the children text into @block. Then I can display all of this child node's text to the screen.
我们为此创建了一个映射，它返回一个我认为的哈希值，{} 中的代码遍历每个节点并将子文本放入 @block 中。然后我可以在屏幕上显示所有这个子节点的文本。
I don't understand this. Although I tried to explain below to show what is Node,and what is Nodesetin Nokogiri. Remember Nodesetis a collection of Nodes.
我不明白这个。虽然我试图下面解释显示什么是节点，什么是节点组中引入nokogiri。记住Nodeset是Nodes的集合。
@chld_class = @block.map do |node|
node.children.class
end
@chld_class
# => [Nokogiri::XML::NodeSet, Nokogiri::XML::NodeSet]
@chld_name = @block.map do |node|
node.children.map { |n| [n.name,n.class] }
end
@chld_name
# => [[["text", Nokogiri::XML::Text],
# ["Title", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["Caption", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["Authors", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["Copyright", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["CreatedDate", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["Keywords", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["ThumbnailSize", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["PreviewSize", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["OriginalSize", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text]],
# [["text", Nokogiri::XML::Text],
# ["Title", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["Caption", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["Authors", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["Copyright", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["CreatedDate", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["Keywords", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["ThumbnailSize", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["PreviewSize", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text],
# ["OriginalSize", Nokogiri::XML::Element],
# ["text", Nokogiri::XML::Text]]]
@chld_name = @block.map do |node|
node.children.map{|n| [n.name,n.text.strip] if n.elem? }.compact
end.compact
@chld_name
# => [[["Title", "Funfair in Bangkok"],
# ["Caption", "A small funfair near On Nut in Bangkok."],
# ["Authors", "Anthony Bouch"],
# ["Copyright", "Copyright ? Anthony Bouch"],
# ["CreatedDate", "2009-08-07T19:22:08"],
# ["Keywords", "Funfair\n Bangkok\n Thailand"],
# ["ThumbnailSize", ""],
# ["PreviewSize", ""],
# ["OriginalSize", ""]],
# [["Title", "Bumper Cars at a Funfair in Bangkok"],
# ["Caption", "Bumper cars at a small funfair near On Nut in Bangkok."],
# ["Authors", "Anthony Bouch"],
# ["Copyright", "Copyright ? Anthony Bouch"],
# ["CreatedDate", "2009-08-03T22:08:24"],
# ["Keywords",
# "Bumper Cars\n Funfair\n Bangkok\n Thailand"],
# ["ThumbnailSize", ""],
# ["PreviewSize", ""],
# ["OriginalSize", ""]]]
回答by orde
The nodes in the sample XML are capitalized, so your code should reflect that. For example:
示例 XML 中的节点是大写的，因此您的代码应该反映这一点。例如：
require 'nokogiri'
doc = Nokogiri::XML(File.open("sample.xml"))
@block = doc.css("Items Item").map { |node| node.children.text }
puts @block
